Source code of SQLite-net (https://github.com/praeclarum/sqlite-net).

SQLite.cs

//
// Copyright (c) 2009-2019 Krueger Systems, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//
#if WINDOWS_PHONE && !USE_WP8_NATIVE_SQLITE
#define USE_CSHARP_SQLITE
#endif

using System;
using System.Collections;
using System.Diagnostics;
#if !USE_SQLITEPCL_RAW
using System.Runtime.InteropServices;
#endif
using System.Collections.Generic;
using System.Reflection;
using System.Linq;
using System.Linq.Expressions;
using System.Text;
using System.Threading;

#if USE_CSHARP_SQLITE
using Sqlite3 = Community.CsharpSqlite.Sqlite3;
using Sqlite3DatabaseHandle = Community.CsharpSqlite.Sqlite3.sqlite3;
using Sqlite3Statement = Community.CsharpSqlite.Sqlite3.Vdbe;
#elif USE_WP8_NATIVE_SQLITE
using Sqlite3 = Sqlite.Sqlite3;
using Sqlite3DatabaseHandle = Sqlite.Database;
using Sqlite3Statement = Sqlite.Statement;
#elif USE_SQLITEPCL_RAW
using Sqlite3DatabaseHandle = SQLitePCL.sqlite3;
using Sqlite3BackupHandle = SQLitePCL.sqlite3_backup;
using Sqlite3Statement = SQLitePCL.sqlite3_stmt;
using Sqlite3 = SQLitePCL.raw;
#else
using Sqlite3DatabaseHandle = System.IntPtr;
using Sqlite3BackupHandle = System.IntPtr;
using Sqlite3Statement = System.IntPtr;
#endif

#pragma warning disable 1591 // XML Doc Comments

namespace SQLite
{
	public class SQLiteException : Exception
	{
		public SQLite3.Result Result { get; private set; }

		protected SQLiteException (SQLite3.Result r, string message) : base (message)
		{
			Result = r;
		}

		public static SQLiteException New (SQLite3.Result r, string message)
		{
			return new SQLiteException (r, message);
		}
	}

	public class NotNullConstraintViolationException : SQLiteException
	{
		public IEnumerable<TableMapping.Column> Columns { get; protected set; }

		protected NotNullConstraintViolationException (SQLite3.Result r, string message)
			: this (r, message, null, null)
		{

		}

		protected NotNullConstraintViolationException (SQLite3.Result r, string message, TableMapping mapping, object obj)
			: base (r, message)
		{
			if (mapping != null && obj != null) {
				this.Columns = from c in mapping.Columns
							   where c.IsNullable == false && c.GetValue (obj) == null
							   select c;
			}
		}

		public static new NotNullConstraintViolationException New (SQLite3.Result r, string message)
		{
			return new NotNullConstraintViolationException (r, message);
		}

		public static NotNullConstraintViolationException New (SQLite3.Result r, string message, TableMapping mapping, object obj)
		{
			return new NotNullConstraintViolationException (r, message, mapping, obj);
		}

		public static NotNullConstraintViolationException New (SQLiteException exception, TableMapping mapping, object obj)
		{
			return new NotNullConstraintViolationException (exception.Result, exception.Message, mapping, obj);
		}
	}

	[Flags]
	public enum SQLiteOpenFlags
	{
		ReadOnly = 1, ReadWrite = 2, Create = 4,
		NoMutex = 0x8000, FullMutex = 0x10000,
		SharedCache = 0x20000, PrivateCache = 0x40000,
		ProtectionComplete = 0x00100000,
		ProtectionCompleteUnlessOpen = 0x00200000,
		ProtectionCompleteUntilFirstUserAuthentication = 0x00300000,
		ProtectionNone = 0x00400000
	}

	[Flags]
	public enum CreateFlags
	{
		/// <summary>
		/// Use the default creation options
		/// </summary>
		None = 0x000,
		/// <summary>
		/// Create a primary key index for a property called 'Id' (case-insensitive).
		/// This avoids the need for the [PrimaryKey] attribute.
		/// </summary>
		ImplicitPK = 0x001,
		/// <summary>
		/// Create indices for properties ending in 'Id' (case-insensitive).
		/// </summary>
		ImplicitIndex = 0x002,
		/// <summary>
		/// Create a primary key for a property called 'Id' and
		/// create an indices for properties ending in 'Id' (case-insensitive).
		/// </summary>
		AllImplicit = 0x003,
		/// <summary>
		/// Force the primary key property to be auto incrementing.
		/// This avoids the need for the [AutoIncrement] attribute.
		/// The primary key property on the class should have type int or long.
		/// </summary>
		AutoIncPK = 0x004,
		/// <summary>
		/// Create virtual table using FTS3
		/// </summary>
		FullTextSearch3 = 0x100,
		/// <summary>
		/// Create virtual table using FTS4
		/// </summary>
		FullTextSearch4 = 0x200
	}

	/// <summary>
	/// An open connection to a SQLite database.
	/// </summary>
	[Preserve (AllMembers = true)]
	public partial class SQLiteConnection : IDisposable
	{
		private bool _open;
		private TimeSpan _busyTimeout;
		readonly static Dictionary<string, TableMapping> _mappings = new Dictionary<string, TableMapping> ();
		private System.Diagnostics.Stopwatch _sw;
		private long _elapsedMilliseconds = 0;

		private int _transactionDepth = 0;
		private Random _rand = new Random ();

		public Sqlite3DatabaseHandle Handle { get; private set; }
		static readonly Sqlite3DatabaseHandle NullHandle = default (Sqlite3DatabaseHandle);
		static readonly Sqlite3BackupHandle NullBackupHandle = default (Sqlite3BackupHandle);

		/// <summary>
		/// Gets the database path used by this connection.
		/// </summary>
		public string DatabasePath { get; private set; }

		/// <summary>
		/// Gets the SQLite library version number. 3007014 would be v3.7.14
		/// </summary>
		public int LibVersionNumber { get; private set; }

		/// <summary>
		/// Whether Trace lines should be written that show the execution time of queries.
		/// </summary>
		public bool TimeExecution { get; set; }

		/// <summary>
		/// Whether to writer queries to <see cref="Tracer"/> during execution.
		/// </summary>
		/// <value>The tracer.</value>
		public bool Trace { get; set; }

		/// <summary>
		/// The delegate responsible for writing trace lines.
		/// </summary>
		/// <value>The tracer.</value>
		public Action<string> Tracer { get; set; }

		/// <summary>
		/// Whether to store DateTime properties as ticks (true) or strings (false).
		/// </summary>
		public bool StoreDateTimeAsTicks { get; private set; }

		/// <summary>
		/// Whether to store TimeSpan properties as ticks (true) or strings (false).
		/// </summary>
		public bool StoreTimeSpanAsTicks { get; private set; }

		/// <summary>
		/// The format to use when storing DateTime properties as strings. Ignored if StoreDateTimeAsTicks is true.
		/// </summary>
		/// <value>The date time string format.</value>
		public string DateTimeStringFormat { get; private set; }

		/// <summary>
		/// The DateTimeStyles value to use when parsing a DateTime property string.
		/// </summary>
		/// <value>The date time style.</value>
		internal System.Globalization.DateTimeStyles DateTimeStyle { get; private set; }

#if USE_SQLITEPCL_RAW && !NO_SQLITEPCL_RAW_BATTERIES
		static SQLiteConnection ()
		{
			SQLitePCL.Batteries_V2.Init ();
		}
#endif

		/// <summary>
		/// Constructs a new SQLiteConnection and opens a SQLite database specified by databasePath.
		/// </summary>
		/// <param name="databasePath">
		/// Specifies the path to the database file.
		/// </param>
		/// <param name="storeDateTimeAsTicks">
		/// Specifies whether to store DateTime properties as ticks (true) or strings (false). You
		/// absolutely do want to store them as Ticks in all new projects. The value of false is
		/// only here for backwards compatibility. There is a *significant* speed advantage, with no
		/// down sides, when setting storeDateTimeAsTicks = true.
		/// If you use DateTimeOffset properties, it will be always stored as ticks regardingless
		/// the storeDateTimeAsTicks parameter.
		/// </param>
		public SQLiteConnection (string databasePath, bool storeDateTimeAsTicks = true)
			: this (new SQLiteConnectionString (databasePath, SQLiteOpenFlags.ReadWrite | SQLiteOpenFlags.Create, storeDateTimeAsTicks))
		{
		}

		/// <summary>
		/// Constructs a new SQLiteConnection and opens a SQLite database specified by databasePath.
		/// </summary>
		/// <param name="databasePath">
		/// Specifies the path to the database file.
		/// </param>
		/// <param name="openFlags">
		/// Flags controlling how the connection should be opened.
		/// </param>
		/// <param name="storeDateTimeAsTicks">
		/// Specifies whether to store DateTime properties as ticks (true) or strings (false). You
		/// absolutely do want to store them as Ticks in all new projects. The value of false is
		/// only here for backwards compatibility. There is a *significant* speed advantage, with no
		/// down sides, when setting storeDateTimeAsTicks = true.
		/// If you use DateTimeOffset properties, it will be always stored as ticks regardingless
		/// the storeDateTimeAsTicks parameter.
		/// </param>
		public SQLiteConnection (string databasePath, SQLiteOpenFlags openFlags, bool storeDateTimeAsTicks = true)
			: this (new SQLiteConnectionString (databasePath, openFlags, storeDateTimeAsTicks))
		{
		}

		/// <summary>
		/// Constructs a new SQLiteConnection and opens a SQLite database specified by databasePath.
		/// </summary>
		/// <param name="connectionString">
		/// Details on how to find and open the database.
		/// </param>
		public SQLiteConnection (SQLiteConnectionString connectionString)
		{
			if (connectionString == null)
				throw new ArgumentNullException (nameof (connectionString));
			if (connectionString.DatabasePath == null)
				throw new InvalidOperationException ("DatabasePath must be specified");

			DatabasePath = connectionString.DatabasePath;

			LibVersionNumber = SQLite3.LibVersionNumber ();

#if NETFX_CORE
			SQLite3.SetDirectory(/*temp directory type*/2, Windows.Storage.ApplicationData.Current.TemporaryFolder.Path);
#endif

			Sqlite3DatabaseHandle handle;

#if SILVERLIGHT || USE_CSHARP_SQLITE || USE_SQLITEPCL_RAW
			var r = SQLite3.Open (connectionString.DatabasePath, out handle, (int)connectionString.OpenFlags, connectionString.VfsName);
#else
			// open using the byte[]
			// in the case where the path may include Unicode
			// force open to using UTF-8 using sqlite3_open_v2
			var databasePathAsBytes = GetNullTerminatedUtf8 (connectionString.DatabasePath);
			var r = SQLite3.Open (databasePathAsBytes, out handle, (int)connectionString.OpenFlags, connectionString.VfsName);
#endif

			Handle = handle;
			if (r != SQLite3.Result.OK) {
				throw SQLiteException.New (r, String.Format ("Could not open database file: {0} ({1})", DatabasePath, r));
			}
			_open = true;

			StoreDateTimeAsTicks = connectionString.StoreDateTimeAsTicks;
			DateTimeStringFormat = connectionString.DateTimeStringFormat;
			DateTimeStyle = connectionString.DateTimeStyle;

			BusyTimeout = TimeSpan.FromSeconds (0.1);
			Tracer = line => Debug.WriteLine (line);

			connectionString.PreKeyAction?.Invoke (this);
			if (connectionString.Key is string stringKey) {
				SetKey (stringKey);
			}
			else if (connectionString.Key is byte[] bytesKey) {
				SetKey (bytesKey);
			}
			else if (connectionString.Key != null) {
				throw new InvalidOperationException ("Encryption keys must be strings or byte arrays");
			}
			connectionString.PostKeyAction?.Invoke (this);
		}

		/// <summary>
		/// Enables the write ahead logging. WAL is significantly faster in most scenarios
		/// by providing better concurrency and better disk IO performance than the normal
		/// jounral mode. You only need to call this function once in the lifetime of the database.
		/// </summary>
		public void EnableWriteAheadLogging()
		{
			ExecuteScalar<string> ("PRAGMA journal_mode=WAL");
		}

		/// <summary>
		/// Convert an input string to a quoted SQL string that can be safely used in queries.
		/// </summary>
		/// <returns>The quoted string.</returns>
		/// <param name="unsafeString">The unsafe string to quote.</param>
		static string Quote (string unsafeString)
		{
			// TODO: Doesn't call sqlite3_mprintf("%Q", u) because we're waiting on https://github.com/ericsink/SQLitePCL.raw/issues/153
			if (unsafeString == null) return "NULL";
			var safe = unsafeString.Replace ("'", "''");
			return "'" + safe + "'";
		}

		/// <summary>
		/// Sets the key used to encrypt/decrypt the database with "pragma key = ...".
		/// This must be the first thing you call before doing anything else with this connection
		/// if your database is encrypted.
		/// This only has an effect if you are using the SQLCipher nuget package.
		/// </summary>
		/// <param name="key">Ecryption key plain text that is converted to the real encryption key using PBKDF2 key derivation</param>
		void SetKey (string key)
		{
			if (key == null) throw new ArgumentNullException (nameof (key));
			var q = Quote (key);
			Execute ("pragma key = " + q);
		}

		/// <summary>
		/// Sets the key used to encrypt/decrypt the database.
		/// This must be the first thing you call before doing anything else with this connection
		/// if your database is encrypted.
		/// This only has an effect if you are using the SQLCipher nuget package.
		/// </summary>
		/// <param name="key">256-bit (32 byte) ecryption key data</param>
		void SetKey (byte[] key)
		{
			if (key == null) throw new ArgumentNullException (nameof (key));
			if (key.Length != 32) throw new ArgumentException ("Key must be 32 bytes (256-bit)", nameof(key));
			var s = String.Join ("", key.Select (x => x.ToString ("X2")));
			Execute ("pragma key = \"x'" + s + "'\"");
		}

		/// <summary>
		/// Enable or disable extension loading.
		/// </summary>
		public void EnableLoadExtension (bool enabled)
		{
			SQLite3.Result r = SQLite3.EnableLoadExtension (Handle, enabled ? 1 : 0);
			if (r != SQLite3.Result.OK) {
				string msg = SQLite3.GetErrmsg (Handle);
				throw SQLiteException.New (r, msg);
			}
		}

#if !USE_SQLITEPCL_RAW
		static byte[] GetNullTerminatedUtf8 (string s)
		{
			var utf8Length = System.Text.Encoding.UTF8.GetByteCount (s);
			var bytes = new byte [utf8Length + 1];
			utf8Length = System.Text.Encoding.UTF8.GetBytes(s, 0, s.Length, bytes, 0);
			return bytes;
		}
#endif

		/// <summary>
		/// Sets a busy handler to sleep the specified amount of time when a table is locked.
		/// The handler will sleep multiple times until a total time of <see cref="BusyTimeout"/> has accumulated.
		/// </summary>
		public TimeSpan BusyTimeout {
			get { return _busyTimeout; }
			set {
				_busyTimeout = value;
				if (Handle != NullHandle) {
					SQLite3.BusyTimeout (Handle, (int)_busyTimeout.TotalMilliseconds);
				}
			}
		}

		/// <summary>
		/// Returns the mappings from types to tables that the connection
		/// currently understands.
		/// </summary>
		public IEnumerable<TableMapping> TableMappings {
			get {
				lock (_mappings) {
					return new List<TableMapping> (_mappings.Values);
				}
			}
		}

		/// <summary>
		/// Retrieves the mapping that is automatically generated for the given type.
		/// </summary>
		/// <param name="type">
		/// The type whose mapping to the database is returned.
		/// </param>
		/// <param name="createFlags">
		/// Optional flags allowing implicit PK and indexes based on naming conventions
		/// </param>
		/// <returns>
		/// The mapping represents the schema of the columns of the database and contains
		/// methods to set and get properties of objects.
		/// </returns>
		public TableMapping GetMapping (Type type, CreateFlags createFlags = CreateFlags.None)
		{
			TableMapping map;
			var key = type.FullName;
			lock (_mappings) {
				if (_mappings.TryGetValue (key, out map)) {
					if (createFlags != CreateFlags.None && createFlags != map.CreateFlags) {
						map = new TableMapping (type, createFlags);
						_mappings[key] = map;
					}
				}
				else {
					map = new TableMapping (type, createFlags);
					_mappings.Add (key, map);
				}
			}
			return map;
		}

		/// <summary>
		/// Retrieves the mapping that is automatically generated for the given type.
		/// </summary>
		/// <param name="createFlags">
		/// Optional flags allowing implicit PK and indexes based on naming conventions
		/// </param>
		/// <returns>
		/// The mapping represents the schema of the columns of the database and contains
		/// methods to set and get properties of objects.
		/// </returns>
		public TableMapping GetMapping<T> (CreateFlags createFlags = CreateFlags.None)
		{
			return GetMapping (typeof (T), createFlags);
		}

		private struct IndexedColumn
		{
			public int Order;
			public string ColumnName;
		}

		private struct IndexInfo
		{
			public string IndexName;
			public string TableName;
			public bool Unique;
			public List<IndexedColumn> Columns;
		}

		/// <summary>
		/// Executes a "drop table" on the database.  This is non-recoverable.
		/// </summary>
		public int DropTable<T> ()
		{
			return DropTable (GetMapping (typeof (T)));
		}

		/// <summary>
		/// Executes a "drop table" on the database.  This is non-recoverable.
		/// </summary>
		/// <param name="map">
		/// The TableMapping used to identify the table.
		/// </param>
		public int DropTable (TableMapping map)
		{
			var query = string.Format ("drop table if exists \"{0}\"", map.TableName);
			return Execute (query);
		}

		/// <summary>
		/// Executes a "create table if not exists" on the database. It also
		/// creates any specified indexes on the columns of the table. It uses
		/// a schema automatically generated from the specified type. You can
		/// later access this schema by calling GetMapping.
		/// </summary>
		/// <returns>
		/// Whether the table was created or migrated.
		/// </returns>
		public CreateTableResult CreateTable<T> (CreateFlags createFlags = CreateFlags.None)
		{
			return CreateTable (typeof (T), createFlags);
		}

		/// <summary>
		/// Executes a "create table if not exists" on the database. It also
		/// creates any specified indexes on the columns of the table. It uses
		/// a schema automatically generated from the specified type. You can
		/// later access this schema by calling GetMapping.
		/// </summary>
		/// <param name="ty">Type to reflect to a database table.</param>
		/// <param name="createFlags">Optional flags allowing implicit PK and indexes based on naming conventions.</param>
		/// <returns>
		/// Whether the table was created or migrated.
		/// </returns>
		public CreateTableResult CreateTable (Type ty, CreateFlags createFlags = CreateFlags.None)
		{
			var map = GetMapping (ty, createFlags);

			// Present a nice error if no columns specified
			if (map.Columns.Length == 0) {
				throw new Exception (string.Format ("Cannot create a table without columns (does '{0}' have public properties?)", ty.FullName));
			}

			// Check if the table exists
			var result = CreateTableResult.Created;
			var existingCols = GetTableInfo (map.TableName);

			// Create or migrate it
			if (existingCols.Count == 0) {

				// Facilitate virtual tables a.k.a. full-text search.
				bool fts3 = (createFlags & CreateFlags.FullTextSearch3) != 0;
				bool fts4 = (createFlags & CreateFlags.FullTextSearch4) != 0;
				bool fts = fts3 || fts4;
				var @virtual = fts ? "virtual " : string.Empty;
				var @using = fts3 ? "using fts3 " : fts4 ? "using fts4 " : string.Empty;

				// Build query.
				var query = "create " + @virtual + "table if not exists \"" + map.TableName + "\" " + @using + "(\n";
				var decls = map.Columns.Select (p => Orm.SqlDecl (p, StoreDateTimeAsTicks, StoreTimeSpanAsTicks));
				var decl = string.Join (",\n", decls.ToArray ());
				query += decl;
				query += ")";
				if(map.WithoutRowId) {
					query += " without rowid";
				}

				Execute (query);
			}
			else {
				result = CreateTableResult.Migrated;
				MigrateTable (map, existingCols);
			}

			var indexes = new Dictionary<string, IndexInfo> ();
			foreach (var c in map.Columns) {
				foreach (var i in c.Indices) {
					var iname = i.Name ?? map.TableName + "_" + c.Name;
					IndexInfo iinfo;
					if (!indexes.TryGetValue (iname, out iinfo)) {
						iinfo = new IndexInfo {
							IndexName = iname,
							TableName = map.TableName,
							Unique = i.Unique,
							Columns = new List<IndexedColumn> ()
						};
						indexes.Add (iname, iinfo);
					}

					if (i.Unique != iinfo.Unique)
						throw new Exception ("All the columns in an index must have the same value for their Unique property");

					iinfo.Columns.Add (new IndexedColumn {
						Order = i.Order,
						ColumnName = c.Name
					});
				}
			}

			foreach (var indexName in indexes.Keys) {
				var index = indexes[indexName];
				var columns = index.Columns.OrderBy (i => i.Order).Select (i => i.ColumnName).ToArray ();
				CreateIndex (indexName, index.TableName, columns, index.Unique);
			}

			return result;
		}

		/// <summary>
		/// Executes a "create table if not exists" on the database for each type. It also
		/// creates any specified indexes on the columns of the table. It uses
		/// a schema automatically generated from the specified type. You can
		/// later access this schema by calling GetMapping.
		/// </summary>
		/// <returns>
		/// Whether the table was created or migrated for each type.
		/// </returns>
		public CreateTablesResult CreateTables<T, T2> (CreateFlags createFlags = CreateFlags.None)
			where T : new()
			where T2 : new()
		{
			return CreateTables (createFlags, typeof (T), typeof (T2));
		}

		/// <summary>
		/// Executes a "create table if not exists" on the database for each type. It also
		/// creates any specified indexes on the columns of the table. It uses
		/// a schema automatically generated from the specified type. You can
		/// later access this schema by calling GetMapping.
		/// </summary>
		/// <returns>
		/// Whether the table was created or migrated for each type.
		/// </returns>
		public CreateTablesResult CreateTables<T, T2, T3> (CreateFlags createFlags = CreateFlags.None)
			where T : new()
			where T2 : new()
			where T3 : new()
		{
			return CreateTables (createFlags, typeof (T), typeof (T2), typeof (T3));
		}

		/// <summary>
		/// Executes a "create table if not exists" on the database for each type. It also
		/// creates any specified indexes on the columns of the table. It uses
		/// a schema automatically generated from the specified type. You can
		/// later access this schema by calling GetMapping.
		/// </summary>
		/// <returns>
		/// Whether the table was created or migrated for each type.
		/// </returns>
		public CreateTablesResult CreateTables<T, T2, T3, T4> (CreateFlags createFlags = CreateFlags.None)
			where T : new()
			where T2 : new()
			where T3 : new()
			where T4 : new()
		{
			return CreateTables (createFlags, typeof (T), typeof (T2), typeof (T3), typeof (T4));
		}

		/// <summary>
		/// Executes a "create table if not exists" on the database for each type. It also
		/// creates any specified indexes on the columns of the table. It uses
		/// a schema automatically generated from the specified type. You can
		/// later access this schema by calling GetMapping.
		/// </summary>
		/// <returns>
		/// Whether the table was created or migrated for each type.
		/// </returns>
		public CreateTablesResult CreateTables<T, T2, T3, T4, T5> (CreateFlags createFlags = CreateFlags.None)
			where T : new()
			where T2 : new()
			where T3 : new()
			where T4 : new()
			where T5 : new()
		{
			return CreateTables (createFlags, typeof (T), typeof (T2), typeof (T3), typeof (T4), typeof (T5));
		}

		/// <summary>
		/// Executes a "create table if not exists" on the database for each type. It also
		/// creates any specified indexes on the columns of the table. It uses
		/// a schema automatically generated from the specified type. You can
		/// later access this schema by calling GetMapping.
		/// </summary>
		/// <returns>
		/// Whether the table was created or migrated for each type.
		/// </returns>
		public CreateTablesResult CreateTables (CreateFlags createFlags = CreateFlags.None, params Type[] types)
		{
			var result = new CreateTablesResult ();
			foreach (Type type in types) {
				var aResult = CreateTable (type, createFlags);
				result.Results[type] = aResult;
			}
			return result;
		}

		/// <summary>
		/// Creates an index for the specified table and columns.
		/// </summary>
		/// <param name="indexName">Name of the index to create</param>
		/// <param name="tableName">Name of the database table</param>
		/// <param name="columnNames">An array of column names to index</param>
		/// <param name="unique">Whether the index should be unique</param>
		public int CreateIndex (string indexName, string tableName, string[] columnNames, bool unique = false)
		{
			const string sqlFormat = "create {2} index if not exists \"{3}\" on \"{0}\"(\"{1}\")";
			var sql = String.Format (sqlFormat, tableName, string.Join ("\", \"", columnNames), unique ? "unique" : "", indexName);
			return Execute (sql);
		}

		/// <summary>
		/// Creates an index for the specified table and column.
		/// </summary>
		/// <param name="indexName">Name of the index to create</param>
		/// <param name="tableName">Name of the database table</param>
		/// <param name="columnName">Name of the column to index</param>
		/// <param name="unique">Whether the index should be unique</param>
		public int CreateIndex (string indexName, string tableName, string columnName, bool unique = false)
		{
			return CreateIndex (indexName, tableName, new string[] { columnName }, unique);
		}

		/// <summary>
		/// Creates an index for the specified table and column.
		/// </summary>
		/// <param name="tableName">Name of the database table</param>
		/// <param name="columnName">Name of the column to index</param>
		/// <param name="unique">Whether the index should be unique</param>
		public int CreateIndex (string tableName, string columnName, bool unique = false)
		{
			return CreateIndex (tableName + "_" + columnName, tableName, columnName, unique);
		}

		/// <summary>
		/// Creates an index for the specified table and columns.
		/// </summary>
		/// <param name="tableName">Name of the database table</param>
		/// <param name="columnNames">An array of column names to index</param>
		/// <param name="unique">Whether the index should be unique</param>
		public int CreateIndex (string tableName, string[] columnNames, bool unique = false)
		{
			return CreateIndex (tableName + "_" + string.Join ("_", columnNames), tableName, columnNames, unique);
		}

		/// <summary>
		/// Creates an index for the specified object property.
		/// e.g. CreateIndex&lt;Client&gt;(c => c.Name);
		/// </summary>
		/// <typeparam name="T">Type to reflect to a database table.</typeparam>
		/// <param name="property">Property to index</param>
		/// <param name="unique">Whether the index should be unique</param>
		public int CreateIndex<T> (Expression<Func<T, object>> property, bool unique = false)
		{
			MemberExpression mx;
			if (property.Body.NodeType == ExpressionType.Convert) {
				mx = ((UnaryExpression)property.Body).Operand as MemberExpression;
			}
			else {
				mx = (property.Body as MemberExpression);
			}
			var propertyInfo = mx.Member as PropertyInfo;
			if (propertyInfo == null) {
				throw new ArgumentException ("The lambda expression 'property' should point to a valid Property");
			}

			var propName = propertyInfo.Name;

			var map = GetMapping<T> ();
			var colName = map.FindColumnWithPropertyName (propName).Name;

			return CreateIndex (map.TableName, colName, unique);
		}

		[Preserve (AllMembers = true)]
		public class ColumnInfo
		{
			//			public int cid { get; set; }

			[Column ("name")]
			public string Name { get; set; }

			//			[Column ("type")]
			//			public string ColumnType { get; set; }

			public int notnull { get; set; }

			//			public string dflt_value { get; set; }

			//			public int pk { get; set; }

			public override string ToString ()
			{
				return Name;
			}
		}

		/// <summary>
		/// Query the built-in sqlite table_info table for a specific tables columns.
		/// </summary>
		/// <returns>The columns contains in the table.</returns>
		/// <param name="tableName">Table name.</param>
		public List<ColumnInfo> GetTableInfo (string tableName)
		{
			var query = "pragma table_info(\"" + tableName + "\")";
			return Query<ColumnInfo> (query);
		}

		void MigrateTable (TableMapping map, List<ColumnInfo> existingCols)
		{
			var toBeAdded = new List<TableMapping.Column> ();

			foreach (var p in map.Columns) {
				var found = false;
				foreach (var c in existingCols) {
					found = (string.Compare (p.Name, c.Name, StringComparison.OrdinalIgnoreCase) == 0);
					if (found)
						break;
				}
				if (!found) {
					toBeAdded.Add (p);
				}
			}

			foreach (var p in toBeAdded) {
				var addCol = "alter table \"" + map.TableName + "\" add column " + Orm.SqlDecl (p, StoreDateTimeAsTicks, StoreTimeSpanAsTicks);
				Execute (addCol);
			}
		}

		/// <summary>
		/// Creates a new SQLiteCommand. Can be overridden to provide a sub-class.
		/// </summary>
		/// <seealso cref="SQLiteCommand.OnInstanceCreated"/>
		protected virtual SQLiteCommand NewCommand ()
		{
			return new SQLiteCommand (this);
		}

		/// <summary>
		/// Creates a new SQLiteCommand given the command text with arguments. Place a '?'
		/// in the command text for each of the arguments.
		/// </summary>
		/// <param name="cmdText">
		/// The fully escaped SQL.
		/// </param>
		/// <param name="ps">
		/// Arguments to substitute for the occurences of '?' in the command text.
		/// </param>
		/// <returns>
		/// A <see cref="SQLiteCommand"/>
		/// </returns>
		public SQLiteCommand CreateCommand (string cmdText, params object[] ps)
		{
			if (!_open)
				throw SQLiteException.New (SQLite3.Result.Error, "Cannot create commands from unopened database");

			var cmd = NewCommand ();
			cmd.CommandText = cmdText;
			foreach (var o in ps) {
				cmd.Bind (o);
			}
			return cmd;
		}

		/// <summary>
		/// Creates a SQLiteCommand given the command text (SQL) with arguments. Place a '?'
		/// in the command text for each of the arguments and then executes that command.
		/// Use this method instead of Query when you don't expect rows back. Such cases include
		/// INSERTs, UPDATEs, and DELETEs.
		/// You can set the Trace or TimeExecution properties of the connection
		/// to profile execution.
		/// </summary>
		/// <param name="query">
		/// The fully escaped SQL.
		/// </param>
		/// <param name="args">
		/// Arguments to substitute for the occurences of '?' in the query.
		/// </param>
		/// <returns>
		/// The number of rows modified in the database as a result of this execution.
		/// </returns>
		public int Execute (string query, params object[] args)
		{
			var cmd = CreateCommand (query, args);

			if (TimeExecution) {
				if (_sw == null) {
					_sw = new Stopwatch ();
				}
				_sw.Reset ();
				_sw.Start ();
			}

			var r = cmd.ExecuteNonQuery ();

			if (TimeExecution) {
				_sw.Stop ();
				_elapsedMilliseconds += _sw.ElapsedMilliseconds;
				Tracer?.Invoke (string.Format ("Finished in {0} ms ({1:0.0} s total)", _sw.ElapsedMilliseconds, _elapsedMilliseconds / 1000.0));
			}

			return r;
		}

		/// <summary>
		/// Creates a SQLiteCommand given the command text (SQL) with arguments. Place a '?'
		/// in the command text for each of the arguments and then executes that command.
		/// Use this method when return primitive values.
		/// You can set the Trace or TimeExecution properties of the connection
		/// to profile execution.
		/// </summary>
		/// <param name="query">
		/// The fully escaped SQL.
		/// </param>
		/// <param name="args">
		/// Arguments to substitute for the occurences of '?' in the query.
		/// </param>
		/// <returns>
		/// The number of rows modified in the database as a result of this execution.
		/// </returns>
		public T ExecuteScalar<T> (string query, params object[] args)
		{
			var cmd = CreateCommand (query, args);

			if (TimeExecution) {
				if (_sw == null) {
					_sw = new Stopwatch ();
				}
				_sw.Reset ();
				_sw.Start ();
			}

			var r = cmd.ExecuteScalar<T> ();

			if (TimeExecution) {
				_sw.Stop ();
				_elapsedMilliseconds += _sw.ElapsedMilliseconds;
				Tracer?.Invoke (string.Format ("Finished in {0} ms ({1:0.0} s total)", _sw.ElapsedMilliseconds, _elapsedMilliseconds / 1000.0));
			}

			return r;
		}

		/// <summary>
		/// Creates a SQLiteCommand given the command text (SQL) with arguments. Place a '?'
		/// in the command text for each of the arguments and then executes that command.
		/// It returns each row of the result using the mapping automatically generated for
		/// the given type.
		/// </summary>
		/// <param name="query">
		/// The fully escaped SQL.
		/// </param>
		/// <param name="args">
		/// Arguments to substitute for the occurences of '?' in the query.
		/// </param>
		/// <returns>
		/// An enumerable with one result for each row returned by the query.
		/// </returns>
		public List<T> Query<T> (string query, params object[] args) where T : new()
		{
			var cmd = CreateCommand (query, args);
			return cmd.ExecuteQuery<T> ();
		}

		/// <summary>
		/// Creates a SQLiteCommand given the command text (SQL) with arguments. Place a '?'
		/// in the command text for each of the arguments and then executes that command.
		/// It returns each row of the result using the mapping automatically generated for
		/// the given type.
		/// </summary>
		/// <param name="query">
		/// The fully escaped SQL.
		/// </param>
		/// <param name="args">
		/// Arguments to substitute for the occurences of '?' in the query.
		/// </param>
		/// <returns>
		/// An enumerable with one result for each row returned by the query.
		/// The enumerator (retrieved by calling GetEnumerator() on the result of this method)
		/// will call sqlite3_step on each call to MoveNext, so the database
		/// connection must remain open for the lifetime of the enumerator.
		/// </returns>
		public IEnumerable<T> DeferredQuery<T> (string query, params object[] args) where T : new()
		{
			var cmd = CreateCommand (query, args);
			return cmd.ExecuteDeferredQuery<T> ();
		}

		/// <summary>
		/// Creates a SQLiteCommand given the command text (SQL) with arguments. Place a '?'
		/// in the command text for each of the arguments and then executes that command.
		/// It returns each row of the result using the specified mapping. This function is
		/// only used by libraries in order to query the database via introspection. It is
		/// normally not used.
		/// </summary>
		/// <param name="map">
		/// A <see cref="TableMapping"/> to use to convert the resulting rows
		/// into objects.
		/// </param>
		/// <param name="query">
		/// The fully escaped SQL.
		/// </param>
		/// <param name="args">
		/// Arguments to substitute for the occurences of '?' in the query.
		/// </param>
		/// <returns>
		/// An enumerable with one result for each row returned by the query.
		/// </returns>
		public List<object> Query (TableMapping map, string query, params object[] args)
		{
			var cmd = CreateCommand (query, args);
			return cmd.ExecuteQuery<object> (map);
		}

		/// <summary>
		/// Creates a SQLiteCommand given the command text (SQL) with arguments. Place a '?'
		/// in the command text for each of the arguments and then executes that command.
		/// It returns each row of the result using the specified mapping. This function is
		/// only used by libraries in order to query the database via introspection. It is
		/// normally not used.
		/// </summary>
		/// <param name="map">
		/// A <see cref="TableMapping"/> to use to convert the resulting rows
		/// into objects.
		/// </param>
		/// <param name="query">
		/// The fully escaped SQL.
		/// </param>
		/// <param name="args">
		/// Arguments to substitute for the occurences of '?' in the query.
		/// </param>
		/// <returns>
		/// An enumerable with one result for each row returned by the query.
		/// The enumerator (retrieved by calling GetEnumerator() on the result of this method)
		/// will call sqlite3_step on each call to MoveNext, so the database
		/// connection must remain open for the lifetime of the enumerator.
		/// </returns>
		public IEnumerable<object> DeferredQuery (TableMapping map, string query, params object[] args)
		{
			var cmd = CreateCommand (query, args);
			return cmd.ExecuteDeferredQuery<object> (map);
		}

		/// <summary>
		/// Returns a queryable interface to the table represented by the given type.
		/// </summary>
		/// <returns>
		/// A queryable object that is able to translate Where, OrderBy, and Take
		/// queries into native SQL.
		/// </returns>
		public TableQuery<T> Table<T> () where T : new()
		{
			return new TableQuery<T> (this);
		}

		/// <summary>
		/// Attempts to retrieve an object with the given primary key from the table
		/// associated with the specified type. Use of this method requires that
		/// the given type have a designated PrimaryKey (using the PrimaryKeyAttribute).
		/// </summary>
		/// <param name="pk">
		/// The primary key.
		/// </param>
		/// <returns>
		/// The object with the given primary key. Throws a not found exception
		/// if the object is not found.
		/// </returns>
		public T Get<T> (object pk) where T : new()
		{
			var map = GetMapping (typeof (T));
			return Query<T> (map.GetByPrimaryKeySql, pk).First ();
		}

		/// <summary>
		/// Attempts to retrieve an object with the given primary key from the table
		/// associated with the specified type. Use of this method requires that
		/// the given type have a designated PrimaryKey (using the PrimaryKeyAttribute).
		/// </summary>
		/// <param name="pk">
		/// The primary key.
		/// </param>
		/// <param name="map">
		/// The TableMapping used to identify the table.
		/// </param>
		/// <returns>
		/// The object with the given primary key. Throws a not found exception
		/// if the object is not found.
		/// </returns>
		public object Get (object pk, TableMapping map)
		{
			return Query (map, map.GetByPrimaryKeySql, pk).First ();
		}

		/// <summary>
		/// Attempts to retrieve the first object that matches the predicate from the table
		/// associated with the specified type.
		/// </summary>
		/// <param name="predicate">
		/// A predicate for which object to find.
		/// </param>
		/// <returns>
		/// The object that matches the given predicate. Throws a not found exception
		/// if the object is not found.
		/// </returns>
		public T Get<T> (Expression<Func<T, bool>> predicate) where T : new()
		{
			return Table<T> ().Where (predicate).First ();
		}

		/// <summary>
		/// Attempts to retrieve an object with the given primary key from the table
		/// associated with the specified type. Use of this method requires that
		/// the given type have a designated PrimaryKey (using the PrimaryKeyAttribute).
		/// </summary>
		/// <param name="pk">
		/// The primary key.
		/// </param>
		/// <returns>
		/// The object with the given primary key or null
		/// if the object is not found.
		/// </returns>
		public T Find<T> (object pk) where T : new()
		{
			var map = GetMapping (typeof (T));
			return Query<T> (map.GetByPrimaryKeySql, pk).FirstOrDefault ();
		}

		/// <summary>
		/// Attempts to retrieve an object with the given primary key from the table
		/// associated with the specified type. Use of this method requires that
		/// the given type have a designated PrimaryKey (using the PrimaryKeyAttribute).
		/// </summary>
		/// <param name="pk">
		/// The primary key.
		/// </param>
		/// <param name="map">
		/// The TableMapping used to identify the table.
		/// </param>
		/// <returns>
		/// The object with the given primary key or null
		/// if the object is not found.
		/// </returns>
		public object Find (object pk, TableMapping map)
		{
			return Query (map, map.GetByPrimaryKeySql, pk).FirstOrDefault ();
		}

		/// <summary>
		/// Attempts to retrieve the first object that matches the predicate from the table
		/// associated with the specified type.
		/// </summary>
		/// <param name="predicate">
		/// A predicate for which object to find.
		/// </param>
		/// <returns>
		/// The object that matches the given predicate or null
		/// if the object is not found.
		/// </returns>
		public T Find<T> (Expression<Func<T, bool>> predicate) where T : new()
		{
			return Table<T> ().Where (predicate).FirstOrDefault ();
		}

		/// <summary>
		/// Attempts to retrieve the first object that matches the query from the table
		/// associated with the specified type.
		/// </summary>
		/// <param name="query">
		/// The fully escaped SQL.
		/// </param>
		/// <param name="args">
		/// Arguments to substitute for the occurences of '?' in the query.
		/// </param>
		/// <returns>
		/// The object that matches the given predicate or null
		/// if the object is not found.
		/// </returns>
		public T FindWithQuery<T> (string query, params object[] args) where T : new()
		{
			return Query<T> (query, args).FirstOrDefault ();
		}

		/// <summary>
		/// Attempts to retrieve the first object that matches the query from the table
		/// associated with the specified type.
		/// </summary>
		/// <param name="map">
		/// The TableMapping used to identify the table.
		/// </param>
		/// <param name="query">
		/// The fully escaped SQL.
		/// </param>
		/// <param name="args">
		/// Arguments to substitute for the occurences of '?' in the query.
		/// </param>
		/// <returns>
		/// The object that matches the given predicate or null
		/// if the object is not found.
		/// </returns>
		public object FindWithQuery (TableMapping map, string query, params object[] args)
		{
			return Query (map, query, args).FirstOrDefault ();
		}

		/// <summary>
		/// Whether <see cref="BeginTransaction"/> has been called and the database is waiting for a <see cref="Commit"/>.
		/// </summary>
		public bool IsInTransaction {
			get { return _transactionDepth > 0; }
		}

		/// <summary>
		/// Begins a new transaction. Call <see cref="Commit"/> to end the transaction.
		/// </summary>
		/// <example cref="System.InvalidOperationException">Throws if a transaction has already begun.</example>
		public void BeginTransaction ()
		{
			// The BEGIN command only works if the transaction stack is empty,
			//    or in other words if there are no pending transactions.
			// If the transaction stack is not empty when the BEGIN command is invoked,
			//    then the command fails with an error.
			// Rather than crash with an error, we will just ignore calls to BeginTransaction
			//    that would result in an error.
			if (Interlocked.CompareExchange (ref _transactionDepth, 1, 0) == 0) {
				try {
					Execute ("begin transaction");
				}
				catch (Exception ex) {
					var sqlExp = ex as SQLiteException;
					if (sqlExp != null) {
						// It is recommended that applications respond to the errors listed below
						//    by explicitly issuing a ROLLBACK command.
						// TODO: This rollback failsafe should be localized to all throw sites.
						switch (sqlExp.Result) {
							case SQLite3.Result.IOError:
							case SQLite3.Result.Full:
							case SQLite3.Result.Busy:
							case SQLite3.Result.NoMem:
							case SQLite3.Result.Interrupt:
								RollbackTo (null, true);
								break;
						}
					}
					else {
						// Call decrement and not VolatileWrite in case we've already
						//    created a transaction point in SaveTransactionPoint since the catch.
						Interlocked.Decrement (ref _transactionDepth);
					}

					throw;
				}
			}
			else {
				// Calling BeginTransaction on an already open transaction is invalid
				throw new InvalidOperationException ("Cannot begin a transaction while already in a transaction.");
			}
		}

		/// <summary>
		/// Creates a savepoint in the database at the current point in the transaction timeline.
		/// Begins a new transaction if one is not in progress.
		///
		/// Call <see cref="RollbackTo(string)"/> to undo transactions since the returned savepoint.
		/// Call <see cref="Release"/> to commit transactions after the savepoint returned here.
		/// Call <see cref="Commit"/> to end the transaction, committing all changes.
		/// </summary>
		/// <returns>A string naming the savepoint.</returns>
		public string SaveTransactionPoint ()
		{
			int depth = Interlocked.Increment (ref _transactionDepth) - 1;
			string retVal = "S" + _rand.Next (short.MaxValue) + "D" + depth;

			try {
				Execute ("savepoint " + retVal);
			}
			catch (Exception ex) {
				var sqlExp = ex as SQLiteException;
				if (sqlExp != null) {
					// It is recommended that applications respond to the errors listed below
					//    by explicitly issuing a ROLLBACK command.
					// TODO: This rollback failsafe should be localized to all throw sites.
					switch (sqlExp.Result) {
						case SQLite3.Result.IOError:
						case SQLite3.Result.Full:
						case SQLite3.Result.Busy:
						case SQLite3.Result.NoMem:
						case SQLite3.Result.Interrupt:
							RollbackTo (null, true);
							break;
					}
				}
				else {
					Interlocked.Decrement (ref _transactionDepth);
				}

				throw;
			}

			return retVal;
		}

		/// <summary>
		/// Rolls back the transaction that was begun by <see cref="BeginTransaction"/> or <see cref="SaveTransactionPoint"/>.
		/// </summary>
		public void Rollback ()
		{
			RollbackTo (null, false);
		}

		/// <summary>
		/// Rolls back the savepoint created by <see cref="BeginTransaction"/> or SaveTransactionPoint.
		/// </summary>
		/// <param name="savepoint">The name of the savepoint to roll back to, as returned by <see cref="SaveTransactionPoint"/>.  If savepoint is null or empty, this method is equivalent to a call to <see cref="Rollback"/></param>
		public void RollbackTo (string savepoint)
		{
			RollbackTo (savepoint, false);
		}

		/// <summary>
		/// Rolls back the transaction that was begun by <see cref="BeginTransaction"/>.
		/// </summary>
		/// <param name="savepoint">The name of the savepoint to roll back to, as returned by <see cref="SaveTransactionPoint"/>.  If savepoint is null or empty, this method is equivalent to a call to <see cref="Rollback"/></param>
		/// <param name="noThrow">true to avoid throwing exceptions, false otherwise</param>
		void RollbackTo (string savepoint, bool noThrow)
		{
			// Rolling back without a TO clause rolls backs all transactions
			//    and leaves the transaction stack empty.
			try {
				if (String.IsNullOrEmpty (savepoint)) {
					if (Interlocked.Exchange (ref _transactionDepth, 0) > 0) {
						Execute ("rollback");
					}
				}
				else {
					DoSavePointExecute (savepoint, "rollback to ");
				}
			}
			catch (SQLiteException) {
				if (!noThrow)
					throw;

			}
			// No need to rollback if there are no transactions open.
		}

		/// <summary>
		/// Releases a savepoint returned from <see cref="SaveTransactionPoint"/>.  Releasing a savepoint
		///    makes changes since that savepoint permanent if the savepoint began the transaction,
		///    or otherwise the changes are permanent pending a call to <see cref="Commit"/>.
		///
		/// The RELEASE command is like a COMMIT for a SAVEPOINT.
		/// </summary>
		/// <param name="savepoint">The name of the savepoint to release.  The string should be the result of a call to <see cref="SaveTransactionPoint"/></param>
		public void Release (string savepoint)
		{
			try {
				DoSavePointExecute (savepoint, "release ");
			}
			catch (SQLiteException ex) {
				if (ex.Result == SQLite3.Result.Busy) {
					// Force a rollback since most people don't know this function can fail
					// Don't call Rollback() since the _transactionDepth is 0 and it won't try
					// Calling rollback makes our _transactionDepth variable correct.
					// Writes to the database only happen at depth=0, so this failure will only happen then.
					try {
						Execute ("rollback");
					}
					catch {
						// rollback can fail in all sorts of wonderful version-dependent ways. Let's just hope for the best
					}
				}
				throw;
			}
		}

		void DoSavePointExecute (string savepoint, string cmd)
		{
			// Validate the savepoint
			int firstLen = savepoint.IndexOf ('D');
			if (firstLen >= 2 && savepoint.Length > firstLen + 1) {
				int depth;
				if (Int32.TryParse (savepoint.Substring (firstLen + 1), out depth)) {
					// TODO: Mild race here, but inescapable without locking almost everywhere.
					if (0 <= depth && depth < _transactionDepth) {
#if NETFX_CORE || USE_SQLITEPCL_RAW || NETCORE
						Volatile.Write (ref _transactionDepth, depth);
#elif SILVERLIGHT
						_transactionDepth = depth;
#else
                        Thread.VolatileWrite (ref _transactionDepth, depth);
#endif
						Execute (cmd + savepoint);
						return;
					}
				}
			}

			throw new ArgumentException ("savePoint is not valid, and should be the result of a call to SaveTransactionPoint.", "savePoint");
		}

		/// <summary>
		/// Commits the transaction that was begun by <see cref="BeginTransaction"/>.
		/// </summary>
		public void Commit ()
		{
			if (Interlocked.Exchange (ref _transactionDepth, 0) != 0) {
				try {
					Execute ("commit");
				}
				catch {
					// Force a rollback since most people don't know this function can fail
					// Don't call Rollback() since the _transactionDepth is 0 and it won't try
					// Calling rollback makes our _transactionDepth variable correct.
					try {
						Execute ("rollback");
					}
					catch {
						// rollback can fail in all sorts of wonderful version-dependent ways. Let's just hope for the best
					}
					throw;
				}
			}
			// Do nothing on a commit with no open transaction
		}

		/// <summary>
		/// Executes <paramref name="action"/> within a (possibly nested) transaction by wrapping it in a SAVEPOINT. If an
		/// exception occurs the whole transaction is rolled back, not just the current savepoint. The exception
		/// is rethrown.
		/// </summary>
		/// <param name="action">
		/// The <see cref="Action"/> to perform within a transaction. <paramref name="action"/> can contain any number
		/// of operations on the connection but should never call <see cref="BeginTransaction"/> or
		/// <see cref="Commit"/>.
		/// </param>
		public void RunInTransaction (Action action)
		{
			try {
				var savePoint = SaveTransactionPoint ();
				action ();
				Release (savePoint);
			}
			catch (Exception) {
				Rollback ();
				throw;
			}
		}

		/// <summary>
		/// Inserts all specified objects.
		/// </summary>
		/// <param name="objects">
		/// An <see cref="IEnumerable"/> of the objects to insert.
		/// <param name="runInTransaction"/>
		/// A boolean indicating if the inserts should be wrapped in a transaction.
		/// </param>
		/// <returns>
		/// The number of rows added to the table.
		/// </returns>
		public int InsertAll (System.Collections.IEnumerable objects, bool runInTransaction = true)
		{
			var c = 0;
			if (runInTransaction) {
				RunInTransaction (() => {
					foreach (var r in objects) {
						c += Insert (r);
					}
				});
			}
			else {
				foreach (var r in objects) {
					c += Insert (r);
				}
			}
			return c;
		}

		/// <summary>
		/// Inserts all specified objects.
		/// </summary>
		/// <param name="objects">
		/// An <see cref="IEnumerable"/> of the objects to insert.
		/// </param>
		/// <param name="extra">
		/// Literal SQL code that gets placed into the command. INSERT {extra} INTO ...
		/// </param>
		/// <param name="runInTransaction">
		/// A boolean indicating if the inserts should be wrapped in a transaction.
		/// </param>
		/// <returns>
		/// The number of rows added to the table.
		/// </returns>
		public int InsertAll (System.Collections.IEnumerable objects, string extra, bool runInTransaction = true)
		{
			var c = 0;
			if (runInTransaction) {
				RunInTransaction (() => {
					foreach (var r in objects) {
						c += Insert (r, extra);
					}
				});
			}
			else {
				foreach (var r in objects) {
					c += Insert (r);
				}
			}
			return c;
		}

		/// <summary>
		/// Inserts all specified objects.
		/// </summary>
		/// <param name="objects">
		/// An <see cref="IEnumerable"/> of the objects to insert.
		/// </param>
		/// <param name="objType">
		/// The type of object to insert.
		/// </param>
		/// <param name="runInTransaction">
		/// A boolean indicating if the inserts should be wrapped in a transaction.
		/// </param>
		/// <returns>
		/// The number of rows added to the table.
		/// </returns>
		public int InsertAll (System.Collections.IEnumerable objects, Type objType, bool runInTransaction = true)
		{
			var c = 0;
			if (runInTransaction) {
				RunInTransaction (() => {
					foreach (var r in objects) {
						c += Insert (r, objType);
					}
				});
			}
			else {
				foreach (var r in objects) {
					c += Insert (r, objType);
				}
			}
			return c;
		}

		/// <summary>
		/// Inserts the given object (and updates its
		/// auto incremented primary key if it has one).
		/// The return value is the number of rows added to the table.
		/// </summary>
		/// <param name="obj">
		/// The object to insert.
		/// </param>
		/// <returns>
		/// The number of rows added to the table.
		/// </returns>
		public int Insert (object obj)
		{
			if (obj == null) {
				return 0;
			}
			return Insert (obj, "", Orm.GetType (obj));
		}

		/// <summary>
		/// Inserts the given object (and updates its
		/// auto incremented primary key if it has one).
		/// The return value is the number of rows added to the table.
		/// If a UNIQUE constraint violation occurs with
		/// some pre-existing object, this function deletes
		/// the old object.
		/// </summary>
		/// <param name="obj">
		/// The object to insert.
		/// </param>
		/// <returns>
		/// The number of rows modified.
		/// </returns>
		public int InsertOrReplace (object obj)
		{
			if (obj == null) {
				return 0;
			}
			return Insert (obj, "OR REPLACE", Orm.GetType (obj));
		}

		/// <summary>
		/// Inserts the given object (and updates its
		/// auto incremented primary key if it has one).
		/// The return value is the number of rows added to the table.
		/// </summary>
		/// <param name="obj">
		/// The object to insert.
		/// </param>
		/// <param name="objType">
		/// The type of object to insert.
		/// </param>
		/// <returns>
		/// The number of rows added to the table.
		/// </returns>
		public int Insert (object obj, Type objType)
		{
			return Insert (obj, "", objType);
		}

		/// <summary>
		/// Inserts the given object (and updates its
		/// auto incremented primary key if it has one).
		/// The return value is the number of rows added to the table.
		/// If a UNIQUE constraint violation occurs with
		/// some pre-existing object, this function deletes
		/// the old object.
		/// </summary>
		/// <param name="obj">
		/// The object to insert.
		/// </param>
		/// <param name="objType">
		/// The type of object to insert.
		/// </param>
		/// <returns>
		/// The number of rows modified.
		/// </returns>
		public int InsertOrReplace (object obj, Type objType)
		{
			return Insert (obj, "OR REPLACE", objType);
		}

		/// <summary>
		/// Inserts the given object (and updates its
		/// auto incremented primary key if it has one).
		/// The return value is the number of rows added to the table.
		/// </summary>
		/// <param name="obj">
		/// The object to insert.
		/// </param>
		/// <param name="extra">
		/// Literal SQL code that gets placed into the command. INSERT {extra} INTO ...
		/// </param>
		/// <returns>
		/// The number of rows added to the table.
		/// </returns>
		public int Insert (object obj, string extra)
		{
			if (obj == null) {
				return 0;
			}
			return Insert (obj, extra, Orm.GetType (obj));
		}

		/// <summary>
		/// Inserts the given object (and updates its
		/// auto incremented primary key if it has one).
		/// The return value is the number of rows added to the table.
		/// </summary>
		/// <param name="obj">
		/// The object to insert.
		/// </param>
		/// <param name="extra">
		/// Literal SQL code that gets placed into the command. INSERT {extra} INTO ...
		/// </param>
		/// <param name="objType">
		/// The type of object to insert.
		/// </param>
		/// <returns>
		/// The number of rows added to the table.
		/// </returns>
		public int Insert (object obj, string extra, Type objType)
		{
			if (obj == null || objType == null) {
				return 0;
			}

			var map = GetMapping (objType);

			if (map.PK != null && map.PK.IsAutoGuid) {
				if (map.PK.GetValue (obj).Equals (Guid.Empty)) {
					map.PK.SetValue (obj, Guid.NewGuid ());
				}
			}

			var replacing = string.Compare (extra, "OR REPLACE", StringComparison.OrdinalIgnoreCase) == 0;

			var cols = replacing ? map.InsertOrReplaceColumns : map.InsertColumns;
			var vals = new object[cols.Length];
			for (var i = 0; i < vals.Length; i++) {
				vals[i] = cols[i].GetValue (obj);
			}

			var insertCmd = GetInsertCommand (map, extra);
			int count;

			lock (insertCmd) {
				// We lock here to protect the prepared statement returned via GetInsertCommand.
				// A SQLite prepared statement can be bound for only one operation at a time.
				try {
					count = insertCmd.ExecuteNonQuery (vals);
				}
				catch (SQLiteException ex) {
					if (SQLite3.ExtendedErrCode (this.Handle) == SQLite3.ExtendedResult.ConstraintNotNull) {
						throw NotNullConstraintViolationException.New (ex.Result, ex.Message, map, obj);
					}
					throw;
				}

				if (map.HasAutoIncPK) {
					var id = SQLite3.LastInsertRowid (Handle);
					map.SetAutoIncPK (obj, id);
				}
			}
			if (count > 0)
				OnTableChanged (map, NotifyTableChangedAction.Insert);

			return count;
		}

		readonly Dictionary<Tuple<string, string>, PreparedSqlLiteInsertCommand> _insertCommandMap = new Dictionary<Tuple<string, string>, PreparedSqlLiteInsertCommand> ();

		PreparedSqlLiteInsertCommand GetInsertCommand (TableMapping map, string extra)
		{
			PreparedSqlLiteInsertCommand prepCmd;

			var key = Tuple.Create (map.MappedType.FullName, extra);

			lock (_insertCommandMap) {
				if (_insertCommandMap.TryGetValue (key, out prepCmd)) {
					return prepCmd;
				}
			}

			prepCmd = CreateInsertCommand (map, extra);
			
			lock (_insertCommandMap) {
				if (_insertCommandMap.TryGetValue (key, out var existing)) {
					prepCmd.Dispose ();
					return existing;
				}

				_insertCommandMap.Add (key, prepCmd);
			}

			return prepCmd;
		}

		PreparedSqlLiteInsertCommand CreateInsertCommand (TableMapping map, string extra)
		{
			var cols = map.InsertColumns;
			string insertSql;
			if (cols.Length == 0 && map.Columns.Length == 1 && map.Columns[0].IsAutoInc) {
				insertSql = string.Format ("insert {1} into \"{0}\" default values", map.TableName, extra);
			}
			else {
				var replacing = string.Compare (extra, "OR REPLACE", StringComparison.OrdinalIgnoreCase) == 0;

				if (replacing) {
					cols = map.InsertOrReplaceColumns;
				}

				insertSql = string.Format ("insert {3} into \"{0}\"({1}) values ({2})", map.TableName,
								   string.Join (",", (from c in cols
													  select "\"" + c.Name + "\"").ToArray ()),
								   string.Join (",", (from c in cols
													  select "?").ToArray ()), extra);

			}

			var insertCommand = new PreparedSqlLiteInsertCommand (this, insertSql);
			return insertCommand;
		}

		/// <summary>
		/// Updates all of the columns of a table using the specified object
		/// except for its primary key.
		/// The object is required to have a primary key.
		/// </summary>
		/// <param name="obj">
		/// The object to update. It must have a primary key designated using the PrimaryKeyAttribute.
		/// </param>
		/// <returns>
		/// The number of rows updated.
		/// </returns>
		public int Update (object obj)
		{
			if (obj == null) {
				return 0;
			}
			return Update (obj, Orm.GetType (obj));
		}

		/// <summary>
		/// Updates all of the columns of a table using the specified object
		/// except for its primary key.
		/// The object is required to have a primary key.
		/// </summary>
		/// <param name="obj">
		/// The object to update. It must have a primary key designated using the PrimaryKeyAttribute.
		/// </param>
		/// <param name="objType">
		/// The type of object to insert.
		/// </param>
		/// <returns>
		/// The number of rows updated.
		/// </returns>
		public int Update (object obj, Type objType)
		{
			int rowsAffected = 0;
			if (obj == null || objType == null) {
				return 0;
			}

			var map = GetMapping (objType);

			var pk = map.PK;

			if (pk == null) {
				throw new NotSupportedException ("Cannot update " + map.TableName + ": it has no PK");
			}

			var cols = from p in map.Columns
					   where p != pk
					   select p;
			var vals = from c in cols
					   select c.GetValue (obj);
			var ps = new List<object> (vals);
			if (ps.Count == 0) {
				// There is a PK but no accompanying data,
				// so reset the PK to make the UPDATE work.
				cols = map.Columns;
				vals = from c in cols
					   select c.GetValue (obj);
				ps = new List<object> (vals);
			}
			ps.Add (pk.GetValue (obj));
			var q = string.Format ("update \"{0}\" set {1} where {2} = ? ", map.TableName, string.Join (",", (from c in cols
																											  select "\"" + c.Name + "\" = ? ").ToArray ()), pk.Name);

			try {
				rowsAffected = Execute (q, ps.ToArray ());
			}
			catch (SQLiteException ex) {

				if (ex.Result == SQLite3.Result.Constraint && SQLite3.ExtendedErrCode (this.Handle) == SQLite3.ExtendedResult.ConstraintNotNull) {
					throw NotNullConstraintViolationException.New (ex, map, obj);
				}

				throw ex;
			}

			if (rowsAffected > 0)
				OnTableChanged (map, NotifyTableChangedAction.Update);

			return rowsAffected;
		}

		/// <summary>
		/// Updates all specified objects.
		/// </summary>
		/// <param name="objects">
		/// An <see cref="IEnumerable"/> of the objects to insert.
		/// </param>
		/// <param name="runInTransaction">
		/// A boolean indicating if the inserts should be wrapped in a transaction
		/// </param>
		/// <returns>
		/// The number of rows modified.
		/// </returns>
		public int UpdateAll (System.Collections.IEnumerable objects, bool runInTransaction = true)
		{
			var c = 0;
			if (runInTransaction) {
				RunInTransaction (() => {
					foreach (var r in objects) {
						c += Update (r);
					}
				});
			}
			else {
				foreach (var r in objects) {
					c += Update (r);
				}
			}
			return c;
		}

		/// <summary>
		/// Deletes the given object from the database using its primary key.
		/// </summary>
		/// <param name="objectToDelete">
		/// The object to delete. It must have a primary key designated using the PrimaryKeyAttribute.
		/// </param>
		/// <returns>
		/// The number of rows deleted.
		/// </returns>
		public int Delete (object objectToDelete)
		{
			var map = GetMapping (Orm.GetType (objectToDelete));
			var pk = map.PK;
			if (pk == null) {
				throw new NotSupportedException ("Cannot delete " + map.TableName + ": it has no PK");
			}
			var q = string.Format ("delete from \"{0}\" where \"{1}\" = ?", map.TableName, pk.Name);
			var count = Execute (q, pk.GetValue (objectToDelete));
			if (count > 0)
				OnTableChanged (map, NotifyTableChangedAction.Delete);
			return count;
		}

		/// <summary>
		/// Deletes the object with the specified primary key.
		/// </summary>
		/// <param name="primaryKey">
		/// The primary key of the object to delete.
		/// </param>
		/// <returns>
		/// The number of objects deleted.
		/// </returns>
		/// <typeparam name='T'>
		/// The type of object.
		/// </typeparam>
		public int Delete<T> (object primaryKey)
		{
			return Delete (primaryKey, GetMapping (typeof (T)));
		}

		/// <summary>
		/// Deletes the object with the specified primary key.
		/// </summary>
		/// <param name="primaryKey">
		/// The primary key of the object to delete.
		/// </param>
		/// <param name="map">
		/// The TableMapping used to identify the table.
		/// </param>
		/// <returns>
		/// The number of objects deleted.
		/// </returns>
		public int Delete (object primaryKey, TableMapping map)
		{
			var pk = map.PK;
			if (pk == null) {
				throw new NotSupportedException ("Cannot delete " + map.TableName + ": it has no PK");
			}
			var q = string.Format ("delete from \"{0}\" where \"{1}\" = ?", map.TableName, pk.Name);
			var count = Execute (q, primaryKey);
			if (count > 0)
				OnTableChanged (map, NotifyTableChangedAction.Delete);
			return count;
		}

		/// <summary>
		/// Deletes all the objects from the specified table.
		/// WARNING WARNING: Let me repeat. It deletes ALL the objects from the
		/// specified table. Do you really want to do that?
		/// </summary>
		/// <returns>
		/// The number of objects deleted.
		/// </returns>
		/// <typeparam name='T'>
		/// The type of objects to delete.
		/// </typeparam>
		public int DeleteAll<T> ()
		{
			var map = GetMapping (typeof (T));
			return DeleteAll (map);
		}

		/// <summary>
		/// Deletes all the objects from the specified table.
		/// WARNING WARNING: Let me repeat. It deletes ALL the objects from the
		/// specified table. Do you really want to do that?
		/// </summary>
		/// <param name="map">
		/// The TableMapping used to identify the table.
		/// </param>
		/// <returns>
		/// The number of objects deleted.
		/// </returns>
		public int DeleteAll (TableMapping map)
		{
			var query = string.Format ("delete from \"{0}\"", map.TableName);
			var count = Execute (query);
			if (count > 0)
				OnTableChanged (map, NotifyTableChangedAction.Delete);
			return count;
		}

		/// <summary>
		/// Backup the entire database to the specified path.
		/// </summary>
		/// <param name="destinationDatabasePath">Path to backup file.</param>
		/// <param name="databaseName">The name of the database to backup (usually "main").</param>
		public void Backup (string destinationDatabasePath, string databaseName = "main")
		{
			// Open the destination
			var r = SQLite3.Open (destinationDatabasePath, out var destHandle);
			if (r != SQLite3.Result.OK) {
				throw SQLiteException.New (r, "Failed to open destination database");
			}

			// Init the backup
			var backup = SQLite3.BackupInit (destHandle, databaseName, Handle, databaseName);
			if (backup == NullBackupHandle) {
				SQLite3.Close (destHandle);
				throw new Exception ("Failed to create backup");
			}

			// Perform it
			SQLite3.BackupStep (backup, -1);
			SQLite3.BackupFinish (backup);

			// Check for errors
			r = SQLite3.GetResult (destHandle);
			string msg = "";
			if (r != SQLite3.Result.OK) {
				msg = SQLite3.GetErrmsg (destHandle);
			}

			// Close everything and report errors
			SQLite3.Close (destHandle);
			if (r != SQLite3.Result.OK) {
				throw SQLiteException.New (r, msg);
			}
		}

		~SQLiteConnection ()
		{
			Dispose (false);
		}

		public void Dispose ()
		{
			Dispose (true);
			GC.SuppressFinalize (this);
		}

		public void Close ()
		{
			Dispose (true);
		}

		protected virtual void Dispose (bool disposing)
		{
			var useClose2 = LibVersionNumber >= 3007014;

			if (_open && Handle != NullHandle) {
				try {
					if (disposing) {
						lock (_insertCommandMap) {
							foreach (var sqlInsertCommand in _insertCommandMap.Values) {
								sqlInsertCommand.Dispose ();
							}
							_insertCommandMap.Clear ();
						}

						var r = useClose2 ? SQLite3.Close2 (Handle) : SQLite3.Close (Handle);
						if (r != SQLite3.Result.OK) {
							string msg = SQLite3.GetErrmsg (Handle);
							throw SQLiteException.New (r, msg);
						}
					}
					else {
						var r = useClose2 ? SQLite3.Close2 (Handle) : SQLite3.Close (Handle);
					}
				}
				finally {
					Handle = NullHandle;
					_open = false;
				}
			}
		}

		void OnTableChanged (TableMapping table, NotifyTableChangedAction action)
		{
			var ev = TableChanged;
			if (ev != null)
				ev (this, new NotifyTableChangedEventArgs (table, action));
		}

		public event EventHandler<NotifyTableChangedEventArgs> TableChanged;
	}

	public class NotifyTableChangedEventArgs : EventArgs
	{
		public TableMapping Table { get; private set; }
		public NotifyTableChangedAction Action { get; private set; }

		public NotifyTableChangedEventArgs (TableMapping table, NotifyTableChangedAction action)
		{
			Table = table;
			Action = action;
		}
	}

	public enum NotifyTableChangedAction
	{
		Insert,
		Update,
		Delete,
	}

	/// <summary>
	/// Represents a parsed connection string.
	/// </summary>
	public class SQLiteConnectionString
	{
		const string DateTimeSqliteDefaultFormat = "yyyy'-'MM'-'dd'T'HH':'mm':'ss'.'fff";

		public string UniqueKey { get; }
		public string DatabasePath { get; }
		public bool StoreDateTimeAsTicks { get; }
		public bool StoreTimeSpanAsTicks { get; }
		public string DateTimeStringFormat { get; }
		public System.Globalization.DateTimeStyles DateTimeStyle { get; }
		public object Key { get; }
		public SQLiteOpenFlags OpenFlags { get; }
		public Action<SQLiteConnection> PreKeyAction { get; }
		public Action<SQLiteConnection> PostKeyAction { get; }
		public string VfsName { get; }

#if NETFX_CORE
		static readonly string MetroStyleDataPath = Windows.Storage.ApplicationData.Current.LocalFolder.Path;

        public static readonly string[] InMemoryDbPaths = new[]
        {
            ":memory:",
            "file::memory:"
        };

        public static bool IsInMemoryPath(string databasePath)
        {
            return InMemoryDbPaths.Any(i => i.Equals(databasePath, StringComparison.OrdinalIgnoreCase));
        }

#endif

		/// <summary>
		/// Constructs a new SQLiteConnectionString with all the data needed to open an SQLiteConnection.
		/// </summary>
		/// <param name="databasePath">
		/// Specifies the path to the database file.
		/// </param>
		/// <param name="storeDateTimeAsTicks">
		/// Specifies whether to store DateTime properties as ticks (true) or strings (false). You
		/// absolutely do want to store them as Ticks in all new projects. The value of false is
		/// only here for backwards compatibility. There is a *significant* speed advantage, with no
		/// down sides, when setting storeDateTimeAsTicks = true.
		/// If you use DateTimeOffset properties, it will be always stored as ticks regardingless
		/// the storeDateTimeAsTicks parameter.
		/// </param>
		public SQLiteConnectionString (string databasePath, bool storeDateTimeAsTicks = true)
			: this (databasePath, SQLiteOpenFlags.Create | SQLiteOpenFlags.ReadWrite, storeDateTimeAsTicks)
		{
		}

		/// <summary>
		/// Constructs a new SQLiteConnectionString with all the data needed to open an SQLiteConnection.
		/// </summary>
		/// <param name="databasePath">
		/// Specifies the path to the database file.
		/// </param>
		/// <param name="storeDateTimeAsTicks">
		/// Specifies whether to store DateTime properties as ticks (true) or strings (false). You
		/// absolutely do want to store them as Ticks in all new projects. The value of false is
		/// only here for backwards compatibility. There is a *significant* speed advantage, with no
		/// down sides, when setting storeDateTimeAsTicks = true.
		/// If you use DateTimeOffset properties, it will be always stored as ticks regardingless
		/// the storeDateTimeAsTicks parameter.
		/// </param>
		/// <param name="key">
		/// Specifies the encryption key to use on the database. Should be a string or a byte[].
		/// </param>
		/// <param name="preKeyAction">
		/// Executes prior to setting key for SQLCipher databases
		/// </param>
		/// <param name="postKeyAction">
		/// Executes after setting key for SQLCipher databases
		/// </param>
		/// <param name="vfsName">
		/// Specifies the Virtual File System to use on the database.
		/// </param>
		public SQLiteConnectionString (string databasePath, bool storeDateTimeAsTicks, object key = null, Action<SQLiteConnection> preKeyAction = null, Action<SQLiteConnection> postKeyAction = null, string vfsName = null)
			: this (databasePath, SQLiteOpenFlags.Create | SQLiteOpenFlags.ReadWrite, storeDateTimeAsTicks, key, preKeyAction, postKeyAction, vfsName)
		{
		}

		/// <summary>
		/// Constructs a new SQLiteConnectionString with all the data needed to open an SQLiteConnection.
		/// </summary>
		/// <param name="databasePath">
		/// Specifies the path to the database file.
		/// </param>
		/// <param name="openFlags">
		/// Flags controlling how the connection should be opened.
		/// </param>
		/// <param name="storeDateTimeAsTicks">
		/// Specifies whether to store DateTime properties as ticks (true) or strings (false). You
		/// absolutely do want to store them as Ticks in all new projects. The value of false is
		/// only here for backwards compatibility. There is a *significant* speed advantage, with no
		/// down sides, when setting storeDateTimeAsTicks = true.
		/// If you use DateTimeOffset properties, it will be always stored as ticks regardingless
		/// the storeDateTimeAsTicks parameter.
		/// </param>
		/// <param name="key">
		/// Specifies the encryption key to use on the database. Should be a string or a byte[].
		/// </param>
		/// <param name="preKeyAction">
		/// Executes prior to setting key for SQLCipher databases
		/// </param>
		/// <param name="postKeyAction">
		/// Executes after setting key for SQLCipher databases
		/// </param>
		/// <param name="vfsName">
		/// Specifies the Virtual File System to use on the database.
		/// </param>
		/// <param name="dateTimeStringFormat">
		/// Specifies the format to use when storing DateTime properties as strings.
		/// </param>
		/// <param name="storeTimeSpanAsTicks">
		/// Specifies whether to store TimeSpan properties as ticks (true) or strings (false). You
		/// absolutely do want to store them as Ticks in all new projects. The value of false is
		/// only here for backwards compatibility. There is a *significant* speed advantage, with no
		/// down sides, when setting storeTimeSpanAsTicks = true.
		/// </param>
		public SQLiteConnectionString (string databasePath, SQLiteOpenFlags openFlags, bool storeDateTimeAsTicks, object key = null, Action<SQLiteConnection> preKeyAction = null, Action<SQLiteConnection> postKeyAction = null, string vfsName = null, string dateTimeStringFormat = DateTimeSqliteDefaultFormat, bool storeTimeSpanAsTicks = true)
		{
			if (key != null && !((key is byte[]) || (key is string)))
				throw new ArgumentException ("Encryption keys must be strings or byte arrays", nameof (key));

			UniqueKey = string.Format ("{0}_{1:X8}", databasePath, (uint)openFlags);
			StoreDateTimeAsTicks = storeDateTimeAsTicks;
			StoreTimeSpanAsTicks = storeTimeSpanAsTicks;
			DateTimeStringFormat = dateTimeStringFormat;
			DateTimeStyle = "o".Equals (DateTimeStringFormat, StringComparison.OrdinalIgnoreCase) || "r".Equals (DateTimeStringFormat, StringComparison.OrdinalIgnoreCase) ? System.Globalization.DateTimeStyles.RoundtripKind : System.Globalization.DateTimeStyles.None;
			Key = key;
			PreKeyAction = preKeyAction;
			PostKeyAction = postKeyAction;
			OpenFlags = openFlags;
			VfsName = vfsName;

#if NETFX_CORE
			DatabasePath = IsInMemoryPath(databasePath)
                ? databasePath
                : System.IO.Path.Combine(MetroStyleDataPath, databasePath);

#else
			DatabasePath = databasePath;
#endif
		}
	}

	[AttributeUsage (AttributeTargets.Class)]
	public class TableAttribute : Attribute
	{
		public string Name { get; set; }

		/// <summary>
		/// Flag whether to create the table without rowid (see https://sqlite.org/withoutrowid.html)
		///
		/// The default is <c>false</c> so that sqlite adds an implicit <c>rowid</c> to every table created.
		/// </summary>
		public bool WithoutRowId { get; set; }

		public TableAttribute (string name)
		{
			Name = name;
		}
	}

	[AttributeUsage (AttributeTargets.Property)]
	public class ColumnAttribute : Attribute
	{
		public string Name { get; set; }

		public ColumnAttribute (string name)
		{
			Name = name;
		}
	}

	[AttributeUsage (AttributeTargets.Property)]
	public class PrimaryKeyAttribute : Attribute
	{
	}

	[AttributeUsage (AttributeTargets.Property)]
	public class AutoIncrementAttribute : Attribute
	{
	}

	[AttributeUsage (AttributeTargets.Property)]
	public class IndexedAttribute : Attribute
	{
		public string Name { get; set; }
		public int Order { get; set; }
		public virtual bool Unique { get; set; }

		public IndexedAttribute ()
		{
		}

		public IndexedAttribute (string name, int order)
		{
			Name = name;
			Order = order;
		}
	}

	[AttributeUsage (AttributeTargets.Property)]
	public class IgnoreAttribute : Attribute
	{
	}

	[AttributeUsage (AttributeTargets.Property)]
	public class UniqueAttribute : IndexedAttribute
	{
		public override bool Unique {
			get { return true; }
			set { /* throw?  */ }
		}
	}

	[AttributeUsage (AttributeTargets.Property)]
	public class MaxLengthAttribute : Attribute
	{
		public int Value { get; private set; }

		public MaxLengthAttribute (int length)
		{
			Value = length;
		}
	}

	public sealed class PreserveAttribute : System.Attribute
	{
		public bool AllMembers;
		public bool Conditional;
	}

	/// <summary>
	/// Select the collating sequence to use on a column.
	/// "BINARY", "NOCASE", and "RTRIM" are supported.
	/// "BINARY" is the default.
	/// </summary>
	[AttributeUsage (AttributeTargets.Property)]
	public class CollationAttribute : Attribute
	{
		public string Value { get; private set; }

		public CollationAttribute (string collation)
		{
			Value = collation;
		}
	}

	[AttributeUsage (AttributeTargets.Property)]
	public class NotNullAttribute : Attribute
	{
	}

	[AttributeUsage (AttributeTargets.Enum)]
	public class StoreAsTextAttribute : Attribute
	{
	}

	public class TableMapping
	{
		public Type MappedType { get; private set; }

		public string TableName { get; private set; }

		public bool WithoutRowId { get; private set; }

		public Column[] Columns { get; private set; }

		public Column PK { get; private set; }

		public string GetByPrimaryKeySql { get; private set; }

		public CreateFlags CreateFlags { get; private set; }

		readonly Column _autoPk;
		readonly Column[] _insertColumns;
		readonly Column[] _insertOrReplaceColumns;

		public TableMapping (Type type, CreateFlags createFlags = CreateFlags.None)
		{
			MappedType = type;
			CreateFlags = createFlags;

			var typeInfo = type.GetTypeInfo ();
			var tableAttr =
				typeInfo.CustomAttributes
						.Where (x => x.AttributeType == typeof (TableAttribute))
						.Select (x => (TableAttribute)Orm.InflateAttribute (x))
						.FirstOrDefault ();

			TableName = (tableAttr != null && !string.IsNullOrEmpty (tableAttr.Name)) ? tableAttr.Name : MappedType.Name;
			WithoutRowId = tableAttr != null ? tableAttr.WithoutRowId : false;

			var props = new List<PropertyInfo> ();
			var baseType = type;
			var propNames = new HashSet<string> ();
			while (baseType != typeof (object)) {
				var ti = baseType.GetTypeInfo ();
				var newProps = (
					from p in ti.DeclaredProperties
					where
						!propNames.Contains (p.Name) &&
						p.CanRead && p.CanWrite &&
						(p.GetMethod != null) && (p.SetMethod != null) &&
						(p.GetMethod.IsPublic && p.SetMethod.IsPublic) &&
						(!p.GetMethod.IsStatic) && (!p.SetMethod.IsStatic)
					select p).ToList ();
				foreach (var p in newProps) {
					propNames.Add (p.Name);
				}
				props.AddRange (newProps);
				baseType = ti.BaseType;
			}

			var cols = new List<Column> ();
			foreach (var p in props) {
				var ignore = p.IsDefined (typeof (IgnoreAttribute), true);
				if (!ignore) {
					cols.Add (new Column (p, createFlags));
				}
			}
			Columns = cols.ToArray ();
			foreach (var c in Columns) {
				if (c.IsAutoInc && c.IsPK) {
					_autoPk = c;
				}
				if (c.IsPK) {
					PK = c;
				}
			}

			HasAutoIncPK = _autoPk != null;

			if (PK != null) {
				GetByPrimaryKeySql = string.Format ("select * from \"{0}\" where \"{1}\" = ?", TableName, PK.Name);
			}
			else {
				// People should not be calling Get/Find without a PK
				GetByPrimaryKeySql = string.Format ("select * from \"{0}\" limit 1", TableName);
			}

			_insertColumns = Columns.Where (c => !c.IsAutoInc).ToArray ();
			_insertOrReplaceColumns = Columns.ToArray ();
		}

		public bool HasAutoIncPK { get; private set; }

		public void SetAutoIncPK (object obj, long id)
		{
			if (_autoPk != null) {
				_autoPk.SetValue (obj, Convert.ChangeType (id, _autoPk.ColumnType, null));
			}
		}

		public Column[] InsertColumns {
			get {
				return _insertColumns;
			}
		}

		public Column[] InsertOrReplaceColumns {
			get {
				return _insertOrReplaceColumns;
			}
		}

		public Column FindColumnWithPropertyName (string propertyName)
		{
			var exact = Columns.FirstOrDefault (c => c.PropertyName == propertyName);
			return exact;
		}

		public Column FindColumn (string columnName)
		{
			var exact = Columns.FirstOrDefault (c => c.Name.ToLower () == columnName.ToLower ());
			return exact;
		}

		public class Column
		{
			PropertyInfo _prop;

			public string Name { get; private set; }

			public PropertyInfo PropertyInfo => _prop;

			public string PropertyName { get { return _prop.Name; } }

			public Type ColumnType { get; private set; }

			public string Collation { get; private set; }

			public bool IsAutoInc { get; private set; }
			public bool IsAutoGuid { get; private set; }

			public bool IsPK { get; private set; }

			public IEnumerable<IndexedAttribute> Indices { get; set; }

			public bool IsNullable { get; private set; }

			public int? MaxStringLength { get; private set; }

			public bool StoreAsText { get; private set; }

			public Column (PropertyInfo prop, CreateFlags createFlags = CreateFlags.None)
			{
				var colAttr = prop.CustomAttributes.FirstOrDefault (x => x.AttributeType == typeof (ColumnAttribute));

				_prop = prop;
				Name = (colAttr != null && colAttr.ConstructorArguments.Count > 0) ?
						colAttr.ConstructorArguments[0].Value?.ToString () :
						prop.Name;
				//If this type is Nullable<T> then Nullable.GetUnderlyingType returns the T, otherwise it returns null, so get the actual type instead
				ColumnType = Nullable.GetUnderlyingType (prop.PropertyType) ?? prop.PropertyType;
				Collation = Orm.Collation (prop);

				IsPK = Orm.IsPK (prop) ||
					(((createFlags & CreateFlags.ImplicitPK) == CreateFlags.ImplicitPK) &&
					 	string.Compare (prop.Name, Orm.ImplicitPkName, StringComparison.OrdinalIgnoreCase) == 0);

				var isAuto = Orm.IsAutoInc (prop) || (IsPK && ((createFlags & CreateFlags.AutoIncPK) == CreateFlags.AutoIncPK));
				IsAutoGuid = isAuto && ColumnType == typeof (Guid);
				IsAutoInc = isAuto && !IsAutoGuid;

				Indices = Orm.GetIndices (prop);
				if (!Indices.Any ()
					&& !IsPK
					&& ((createFlags & CreateFlags.ImplicitIndex) == CreateFlags.ImplicitIndex)
					&& Name.EndsWith (Orm.ImplicitIndexSuffix, StringComparison.OrdinalIgnoreCase)
					) {
					Indices = new IndexedAttribute[] { new IndexedAttribute () };
				}
				IsNullable = !(IsPK || Orm.IsMarkedNotNull (prop));
				MaxStringLength = Orm.MaxStringLength (prop);

				StoreAsText = prop.PropertyType.GetTypeInfo ().CustomAttributes.Any (x => x.AttributeType == typeof (StoreAsTextAttribute));
			}

			public void SetValue (object obj, object val)
			{
				if (val != null && ColumnType.GetTypeInfo ().IsEnum) {
					_prop.SetValue (obj, Enum.ToObject (ColumnType, val));
				}
				else {
					_prop.SetValue (obj, val, null);
				}
			}

			public object GetValue (object obj)
			{
				return _prop.GetValue (obj, null);
			}
		}
	}

	class EnumCacheInfo
	{
		public EnumCacheInfo (Type type)
		{
			var typeInfo = type.GetTypeInfo ();

			IsEnum = typeInfo.IsEnum;

			if (IsEnum) {
				StoreAsText = typeInfo.CustomAttributes.Any (x => x.AttributeType == typeof (StoreAsTextAttribute));

				if (StoreAsText) {
					EnumValues = new Dictionary<int, string> ();
					foreach (object e in Enum.GetValues (type)) {
						EnumValues[Convert.ToInt32 (e)] = e.ToString ();
					}
				}
			}
		}

		public bool IsEnum { get; private set; }

		public bool StoreAsText { get; private set; }

		public Dictionary<int, string> EnumValues { get; private set; }
	}

	static class EnumCache
	{
		static readonly Dictionary<Type, EnumCacheInfo> Cache = new Dictionary<Type, EnumCacheInfo> ();

		public static EnumCacheInfo GetInfo<T> ()
		{
			return GetInfo (typeof (T));
		}

		public static EnumCacheInfo GetInfo (Type type)
		{
			lock (Cache) {
				EnumCacheInfo info = null;
				if (!Cache.TryGetValue (type, out info)) {
					info = new EnumCacheInfo (type);
					Cache[type] = info;
				}

				return info;
			}
		}
	}

	public static class Orm
	{
		public const int DefaultMaxStringLength = 140;
		public const string ImplicitPkName = "Id";
		public const string ImplicitIndexSuffix = "Id";

		public static Type GetType (object obj)
		{
			if (obj == null)
				return typeof (object);
			var rt = obj as IReflectableType;
			if (rt != null)
				return rt.GetTypeInfo ().AsType ();
			return obj.GetType ();
		}

		public static string SqlDecl (TableMapping.Column p, bool storeDateTimeAsTicks, bool storeTimeSpanAsTicks)
		{
			string decl = "\"" + p.Name + "\" " + SqlType (p, storeDateTimeAsTicks, storeTimeSpanAsTicks) + " ";

			if (p.IsPK) {
				decl += "primary key ";
			}
			if (p.IsAutoInc) {
				decl += "autoincrement ";
			}
			if (!p.IsNullable) {
				decl += "not null ";
			}
			if (!string.IsNullOrEmpty (p.Collation)) {
				decl += "collate " + p.Collation + " ";
			}

			return decl;
		}

		public static string SqlType (TableMapping.Column p, bool storeDateTimeAsTicks, bool storeTimeSpanAsTicks)
		{
			var clrType = p.ColumnType;
			if (clrType == typeof (Boolean) || clrType == typeof (Byte) || clrType == typeof (UInt16) || clrType == typeof (SByte) || clrType == typeof (Int16) || clrType == typeof (Int32) || clrType == typeof (UInt32) || clrType == typeof (Int64)) {
				return "integer";
			}
			else if (clrType == typeof (Single) || clrType == typeof (Double) || clrType == typeof (Decimal)) {
				return "float";
			}
			else if (clrType == typeof (String) || clrType == typeof (StringBuilder) || clrType == typeof (Uri) || clrType == typeof (UriBuilder)) {
				int? len = p.MaxStringLength;

				if (len.HasValue)
					return "varchar(" + len.Value + ")";

				return "varchar";
			}
			else if (clrType == typeof (TimeSpan)) {
				return storeTimeSpanAsTicks ? "bigint" : "time";
			}
			else if (clrType == typeof (DateTime)) {
				return storeDateTimeAsTicks ? "bigint" : "datetime";
			}
			else if (clrType == typeof (DateTimeOffset)) {
				return "bigint";
			}
			else if (clrType.GetTypeInfo ().IsEnum) {
				if (p.StoreAsText)
					return "varchar";
				else
					return "integer";
			}
			else if (clrType == typeof (byte[])) {
				return "blob";
			}
			else if (clrType == typeof (Guid)) {
				return "varchar(36)";
			}
			else {
				throw new NotSupportedException ("Don't know about " + clrType);
			}
		}

		public static bool IsPK (MemberInfo p)
		{
			return p.CustomAttributes.Any (x => x.AttributeType == typeof (PrimaryKeyAttribute));
		}

		public static string Collation (MemberInfo p)
		{
			return
				(p.CustomAttributes
				 .Where (x => typeof (CollationAttribute) == x.AttributeType)
				 .Select (x => {
					 var args = x.ConstructorArguments;
					 return args.Count > 0 ? ((args[0].Value as string) ?? "") : "";
				 })
				 .FirstOrDefault ()) ?? "";
		}

		public static bool IsAutoInc (MemberInfo p)
		{
			return p.CustomAttributes.Any (x => x.AttributeType == typeof (AutoIncrementAttribute));
		}

		public static FieldInfo GetField (TypeInfo t, string name)
		{
			var f = t.GetDeclaredField (name);
			if (f != null)
				return f;
			return GetField (t.BaseType.GetTypeInfo (), name);
		}

		public static PropertyInfo GetProperty (TypeInfo t, string name)
		{
			var f = t.GetDeclaredProperty (name);
			if (f != null)
				return f;
			return GetProperty (t.BaseType.GetTypeInfo (), name);
		}

		public static object InflateAttribute (CustomAttributeData x)
		{
			var atype = x.AttributeType;
			var typeInfo = atype.GetTypeInfo ();
			var args = x.ConstructorArguments.Select (a => a.Value).ToArray ();
			var r = Activator.CreateInstance (x.AttributeType, args);
			foreach (var arg in x.NamedArguments) {
				if (arg.IsField) {
					GetField (typeInfo, arg.MemberName).SetValue (r, arg.TypedValue.Value);
				}
				else {
					GetProperty (typeInfo, arg.MemberName).SetValue (r, arg.TypedValue.Value);
				}
			}
			return r;
		}

		public static IEnumerable<IndexedAttribute> GetIndices (MemberInfo p)
		{
			var indexedInfo = typeof (IndexedAttribute).GetTypeInfo ();
			return
				p.CustomAttributes
				 .Where (x => indexedInfo.IsAssignableFrom (x.AttributeType.GetTypeInfo ()))
				 .Select (x => (IndexedAttribute)InflateAttribute (x));
		}

		public static int? MaxStringLength (PropertyInfo p)
		{
			var attr = p.CustomAttributes.FirstOrDefault (x => x.AttributeType == typeof (MaxLengthAttribute));
			if (attr != null) {
				var attrv = (MaxLengthAttribute)InflateAttribute (attr);
				return attrv.Value;
			}
			return null;
		}

		public static bool IsMarkedNotNull (MemberInfo p)
		{
			return p.CustomAttributes.Any (x => x.AttributeType == typeof (NotNullAttribute));
		}
	}

	public partial class SQLiteCommand
	{
		SQLiteConnection _conn;
		private List<Binding> _bindings;

		public string CommandText { get; set; }

		public SQLiteCommand (SQLiteConnection conn)
		{
			_conn = conn;
			_bindings = new List<Binding> ();
			CommandText = "";
		}

		public int ExecuteNonQuery ()
		{
			if (_conn.Trace) {
				_conn.Tracer?.Invoke ("Executing: " + this);
			}

			var r = SQLite3.Result.OK;
			var stmt = Prepare ();
			r = SQLite3.Step (stmt);
			Finalize (stmt);
			if (r == SQLite3.Result.Done) {
				int rowsAffected = SQLite3.Changes (_conn.Handle);
				return rowsAffected;
			}
			else if (r == SQLite3.Result.Error) {
				string msg = SQLite3.GetErrmsg (_conn.Handle);
				throw SQLiteException.New (r, msg);
			}
			else if (r == SQLite3.Result.Constraint) {
				if (SQLite3.ExtendedErrCode (_conn.Handle) == SQLite3.ExtendedResult.ConstraintNotNull) {
					throw NotNullConstraintViolationException.New (r, SQLite3.GetErrmsg (_conn.Handle));
				}
			}

			throw SQLiteException.New (r, r.ToString ());
		}

		public IEnumerable<T> ExecuteDeferredQuery<T> ()
		{
			return ExecuteDeferredQuery<T> (_conn.GetMapping (typeof (T)));
		}

		public List<T> ExecuteQuery<T> ()
		{
			return ExecuteDeferredQuery<T> (_conn.GetMapping (typeof (T))).ToList ();
		}

		public List<T> ExecuteQuery<T> (TableMapping map)
		{
			return ExecuteDeferredQuery<T> (map).ToList ();
		}

		/// <summary>
		/// Invoked every time an instance is loaded from the database.
		/// </summary>
		/// <param name='obj'>
		/// The newly created object.
		/// </param>
		/// <remarks>
		/// This can be overridden in combination with the <see cref="SQLiteConnection.NewCommand"/>
		/// method to hook into the life-cycle of objects.
		/// </remarks>
		protected virtual void OnInstanceCreated (object obj)
		{
			// Can be overridden.
		}

		public IEnumerable<T> ExecuteDeferredQuery<T> (TableMapping map)
		{
			if (_conn.Trace) {
				_conn.Tracer?.Invoke ("Executing Query: " + this);
			}

			var stmt = Prepare ();
			try {
				var cols = new TableMapping.Column[SQLite3.ColumnCount (stmt)];

				for (int i = 0; i < cols.Length; i++) {
					var name = SQLite3.ColumnName16 (stmt, i);
					cols[i] = map.FindColumn (name);
				}

				while (SQLite3.Step (stmt) == SQLite3.Result.Row) {
					var obj = Activator.CreateInstance (map.MappedType);
					for (int i = 0; i < cols.Length; i++) {
						if (cols[i] == null)
							continue;
						var colType = SQLite3.ColumnType (stmt, i);
						var val = ReadCol (stmt, i, colType, cols[i].ColumnType);
						cols[i].SetValue (obj, val);
					}
					OnInstanceCreated (obj);
					yield return (T)obj;
				}
			}
			finally {
				SQLite3.Finalize (stmt);
			}
		}

		public T ExecuteScalar<T> ()
		{
			if (_conn.Trace) {
				_conn.Tracer?.Invoke ("Executing Query: " + this);
			}

			T val = default (T);

			var stmt = Prepare ();

			try {
				var r = SQLite3.Step (stmt);
				if (r == SQLite3.Result.Row) {
					var colType = SQLite3.ColumnType (stmt, 0);
					val = (T)ReadCol (stmt, 0, colType, typeof (T));
				}
				else if (r == SQLite3.Result.Done) {
				}
				else {
					throw SQLiteException.New (r, SQLite3.GetErrmsg (_conn.Handle));
				}
			}
			finally {
				Finalize (stmt);
			}

			return val;
		}

		public void Bind (string name, object val)
		{
			_bindings.Add (new Binding {
				Name = name,
				Value = val
			});
		}

		public void Bind (object val)
		{
			Bind (null, val);
		}

		public override string ToString ()
		{
			var parts = new string[1 + _bindings.Count];
			parts[0] = CommandText;
			var i = 1;
			foreach (var b in _bindings) {
				parts[i] = string.Format ("  {0}: {1}", i - 1, b.Value);
				i++;
			}
			return string.Join (Environment.NewLine, parts);
		}

		Sqlite3Statement Prepare ()
		{
			var stmt = SQLite3.Prepare2 (_conn.Handle, CommandText);
			BindAll (stmt);
			return stmt;
		}

		void Finalize (Sqlite3Statement stmt)
		{
			SQLite3.Finalize (stmt);
		}

		void BindAll (Sqlite3Statement stmt)
		{
			int nextIdx = 1;
			foreach (var b in _bindings) {
				if (b.Name != null) {
					b.Index = SQLite3.BindParameterIndex (stmt, b.Name);
				}
				else {
					b.Index = nextIdx++;
				}

				BindParameter (stmt, b.Index, b.Value, _conn.StoreDateTimeAsTicks, _conn.DateTimeStringFormat, _conn.StoreTimeSpanAsTicks);
			}
		}

		static IntPtr NegativePointer = new IntPtr (-1);

		internal static void BindParameter (Sqlite3Statement stmt, int index, object value, bool storeDateTimeAsTicks, string dateTimeStringFormat, bool storeTimeSpanAsTicks)
		{
			if (value == null) {
				SQLite3.BindNull (stmt, index);
			}
			else {
				if (value is Int32) {
					SQLite3.BindInt (stmt, index, (int)value);
				}
				else if (value is String) {
					SQLite3.BindText (stmt, index, (string)value, -1, NegativePointer);
				}
				else if (value is Byte || value is UInt16 || value is SByte || value is Int16) {
					SQLite3.BindInt (stmt, index, Convert.ToInt32 (value));
				}
				else if (value is Boolean) {
					SQLite3.BindInt (stmt, index, (bool)value ? 1 : 0);
				}
				else if (value is UInt32 || value is Int64) {
					SQLite3.BindInt64 (stmt, index, Convert.ToInt64 (value));
				}
				else if (value is Single || value is Double || value is Decimal) {
					SQLite3.BindDouble (stmt, index, Convert.ToDouble (value));
				}
				else if (value is TimeSpan) {
					if (storeTimeSpanAsTicks) {
						SQLite3.BindInt64 (stmt, index, ((TimeSpan)value).Ticks);
					}
					else {
						SQLite3.BindText (stmt, index, ((TimeSpan)value).ToString (), -1, NegativePointer);
					}
				}
				else if (value is DateTime) {
					if (storeDateTimeAsTicks) {
						SQLite3.BindInt64 (stmt, index, ((DateTime)value).Ticks);
					}
					else {
						SQLite3.BindText (stmt, index, ((DateTime)value).ToString (dateTimeStringFormat, System.Globalization.CultureInfo.InvariantCulture), -1, NegativePointer);
					}
				}
				else if (value is DateTimeOffset) {
					SQLite3.BindInt64 (stmt, index, ((DateTimeOffset)value).UtcTicks);
				}
				else if (value is byte[]) {
					SQLite3.BindBlob (stmt, index, (byte[])value, ((byte[])value).Length, NegativePointer);
				}
				else if (value is Guid) {
					SQLite3.BindText (stmt, index, ((Guid)value).ToString (), 72, NegativePointer);
				}
				else if (value is Uri) {
					SQLite3.BindText (stmt, index, ((Uri)value).ToString (), -1, NegativePointer);
				}
				else if (value is StringBuilder) {
					SQLite3.BindText (stmt, index, ((StringBuilder)value).ToString (), -1, NegativePointer);
				}
				else if (value is UriBuilder) {
					SQLite3.BindText (stmt, index, ((UriBuilder)value).ToString (), -1, NegativePointer);
				}
				else {
					// Now we could possibly get an enum, retrieve cached info
					var valueType = value.GetType ();
					var enumInfo = EnumCache.GetInfo (valueType);
					if (enumInfo.IsEnum) {
						var enumIntValue = Convert.ToInt32 (value);
						if (enumInfo.StoreAsText)
							SQLite3.BindText (stmt, index, enumInfo.EnumValues[enumIntValue], -1, NegativePointer);
						else
							SQLite3.BindInt (stmt, index, enumIntValue);
					}
					else {
						throw new NotSupportedException ("Cannot store type: " + Orm.GetType (value));
					}
				}
			}
		}

		class Binding
		{
			public string Name { get; set; }

			public object Value { get; set; }

			public int Index { get; set; }
		}

		object ReadCol (Sqlite3Statement stmt, int index, SQLite3.ColType type, Type clrType)
		{
			if (type == SQLite3.ColType.Null) {
				return null;
			}
			else {
				var clrTypeInfo = clrType.GetTypeInfo ();
				if (clrTypeInfo.IsGenericType && clrTypeInfo.GetGenericTypeDefinition () == typeof (Nullable<>)) {
					clrType = clrTypeInfo.GenericTypeArguments[0];
					clrTypeInfo = clrType.GetTypeInfo ();
				}

				if (clrType == typeof (String)) {
					return SQLite3.ColumnString (stmt, index);
				}
				else if (clrType == typeof (Int32)) {
					return (int)SQLite3.ColumnInt (stmt, index);
				}
				else if (clrType == typeof (Boolean)) {
					return SQLite3.ColumnInt (stmt, index) == 1;
				}
				else if (clrType == typeof (double)) {
					return SQLite3.ColumnDouble (stmt, index);
				}
				else if (clrType == typeof (float)) {
					return (float)SQLite3.ColumnDouble (stmt, index);
				}
				else if (clrType == typeof (TimeSpan)) {
					if (_conn.StoreTimeSpanAsTicks) {
						return new TimeSpan (SQLite3.ColumnInt64 (stmt, index));
					}
					else {
						var text = SQLite3.ColumnString (stmt, index);
						TimeSpan resultTime;
						if (!TimeSpan.TryParseExact (text, "c", System.Globalization.CultureInfo.InvariantCulture, System.Globalization.TimeSpanStyles.None, out resultTime)) {
							resultTime = TimeSpan.Parse (text);
						}
						return resultTime;
					}
				}
				else if (clrType == typeof (DateTime)) {
					if (_conn.StoreDateTimeAsTicks) {
						return new DateTime (SQLite3.ColumnInt64 (stmt, index));
					}
					else {
						var text = SQLite3.ColumnString (stmt, index);
						DateTime resultDate;
						if (!DateTime.TryParseExact (text, _conn.DateTimeStringFormat, System.Globalization.CultureInfo.InvariantCulture, _conn.DateTimeStyle, out resultDate)) {
							resultDate = DateTime.Parse (text);
						}
						return resultDate;
					}
				}
				else if (clrType == typeof (DateTimeOffset)) {
					return new DateTimeOffset (SQLite3.ColumnInt64 (stmt, index), TimeSpan.Zero);
				}
				else if (clrTypeInfo.IsEnum) {
					if (type == SQLite3.ColType.Text) {
						var value = SQLite3.ColumnString (stmt, index);
						return Enum.Parse (clrType, value.ToString (), true);
					}
					else
						return SQLite3.ColumnInt (stmt, index);
				}
				else if (clrType == typeof (Int64)) {
					return SQLite3.ColumnInt64 (stmt, index);
				}
				else if (clrType == typeof (UInt32)) {
					return (uint)SQLite3.ColumnInt64 (stmt, index);
				}
				else if (clrType == typeof (decimal)) {
					return (decimal)SQLite3.ColumnDouble (stmt, index);
				}
				else if (clrType == typeof (Byte)) {
					return (byte)SQLite3.ColumnInt (stmt, index);
				}
				else if (clrType == typeof (UInt16)) {
					return (ushort)SQLite3.ColumnInt (stmt, index);
				}
				else if (clrType == typeof (Int16)) {
					return (short)SQLite3.ColumnInt (stmt, index);
				}
				else if (clrType == typeof (sbyte)) {
					return (sbyte)SQLite3.ColumnInt (stmt, index);
				}
				else if (clrType == typeof (byte[])) {
					return SQLite3.ColumnByteArray (stmt, index);
				}
				else if (clrType == typeof (Guid)) {
					var text = SQLite3.ColumnString (stmt, index);
					return new Guid (text);
				}
                else if (clrType == typeof(Uri)) {
                    var text = SQLite3.ColumnString(stmt, index);
                    return new Uri(text);
                }
				else if (clrType == typeof (StringBuilder)) {
					var text = SQLite3.ColumnString (stmt, index);
					return new StringBuilder (text);
				}
				else if (clrType == typeof(UriBuilder)) {
                    var text = SQLite3.ColumnString(stmt, index);
                    return new UriBuilder(text);
                }
				else {
					throw new NotSupportedException ("Don't know how to read " + clrType);
				}
			}
		}
	}

	/// <summary>
	/// Since the insert never changed, we only need to prepare once.
	/// </summary>
	class PreparedSqlLiteInsertCommand : IDisposable
	{
		bool Initialized;

		SQLiteConnection Connection;

		string CommandText;

		Sqlite3Statement Statement;
		static readonly Sqlite3Statement NullStatement = default (Sqlite3Statement);

		public PreparedSqlLiteInsertCommand (SQLiteConnection conn, string commandText)
		{
			Connection = conn;
			CommandText = commandText;
		}

		public int ExecuteNonQuery (object[] source)
		{
			if (Initialized && Statement == NullStatement) {
				throw new ObjectDisposedException (nameof (PreparedSqlLiteInsertCommand));
			}

			if (Connection.Trace) {
				Connection.Tracer?.Invoke ("Executing: " + CommandText);
			}

			var r = SQLite3.Result.OK;

			if (!Initialized) {
				Statement = SQLite3.Prepare2 (Connection.Handle, CommandText);
				Initialized = true;
			}

			//bind the values.
			if (source != null) {
				for (int i = 0; i < source.Length; i++) {
					SQLiteCommand.BindParameter (Statement, i + 1, source[i], Connection.StoreDateTimeAsTicks, Connection.DateTimeStringFormat, Connection.StoreTimeSpanAsTicks);
				}
			}
			r = SQLite3.Step (Statement);

			if (r == SQLite3.Result.Done) {
				int rowsAffected = SQLite3.Changes (Connection.Handle);
				SQLite3.Reset (Statement);
				return rowsAffected;
			}
			else if (r == SQLite3.Result.Error) {
				string msg = SQLite3.GetErrmsg (Connection.Handle);
				SQLite3.Reset (Statement);
				throw SQLiteException.New (r, msg);
			}
			else if (r == SQLite3.Result.Constraint && SQLite3.ExtendedErrCode (Connection.Handle) == SQLite3.ExtendedResult.ConstraintNotNull) {
				SQLite3.Reset (Statement);
				throw NotNullConstraintViolationException.New (r, SQLite3.GetErrmsg (Connection.Handle));
			}
			else {
				SQLite3.Reset (Statement);
				throw SQLiteException.New (r, r.ToString ());
			}
		}

		public void Dispose ()
		{
			Dispose (true);
			GC.SuppressFinalize (this);
		}

		void Dispose (bool disposing)
		{
			var s = Statement;
			Statement = NullStatement;
			Connection = null;
			if (s != NullStatement) {
				SQLite3.Finalize (s);
			}
		}

		~PreparedSqlLiteInsertCommand ()
		{
			Dispose (false);
		}
	}

	public enum CreateTableResult
	{
		Created,
		Migrated,
	}

	public class CreateTablesResult
	{
		public Dictionary<Type, CreateTableResult> Results { get; private set; }

		public CreateTablesResult ()
		{
			Results = new Dictionary<Type, CreateTableResult> ();
		}
	}

	public abstract class BaseTableQuery
	{
		protected class Ordering
		{
			public string ColumnName { get; set; }
			public bool Ascending { get; set; }
		}
	}

	public class TableQuery<T> : BaseTableQuery, IEnumerable<T>
	{
		public SQLiteConnection Connection { get; private set; }

		public TableMapping Table { get; private set; }

		Expression _where;
		List<Ordering> _orderBys;
		int? _limit;
		int? _offset;

		BaseTableQuery _joinInner;
		Expression _joinInnerKeySelector;
		BaseTableQuery _joinOuter;
		Expression _joinOuterKeySelector;
		Expression _joinSelector;

		Expression _selector;

		TableQuery (SQLiteConnection conn, TableMapping table)
		{
			Connection = conn;
			Table = table;
		}

		public TableQuery (SQLiteConnection conn)
		{
			Connection = conn;
			Table = Connection.GetMapping (typeof (T));
		}

		public TableQuery<U> Clone<U> ()
		{
			var q = new TableQuery<U> (Connection, Table);
			q._where = _where;
			q._deferred = _deferred;
			if (_orderBys != null) {
				q._orderBys = new List<Ordering> (_orderBys);
			}
			q._limit = _limit;
			q._offset = _offset;
			q._joinInner = _joinInner;
			q._joinInnerKeySelector = _joinInnerKeySelector;
			q._joinOuter = _joinOuter;
			q._joinOuterKeySelector = _joinOuterKeySelector;
			q._joinSelector = _joinSelector;
			q._selector = _selector;
			return q;
		}

		/// <summary>
		/// Filters the query based on a predicate.
		/// </summary>
		public TableQuery<T> Where (Expression<Func<T, bool>> predExpr)
		{
			if (predExpr.NodeType == ExpressionType.Lambda) {
				var lambda = (LambdaExpression)predExpr;
				var pred = lambda.Body;
				var q = Clone<T> ();
				q.AddWhere (pred);
				return q;
			}
			else {
				throw new NotSupportedException ("Must be a predicate");
			}
		}

		/// <summary>
		/// Delete all the rows that match this query.
		/// </summary>
		public int Delete ()
		{
			return Delete (null);
		}

		/// <summary>
		/// Delete all the rows that match this query and the given predicate.
		/// </summary>
		public int Delete (Expression<Func<T, bool>> predExpr)
		{
			if (_limit.HasValue || _offset.HasValue)
				throw new InvalidOperationException ("Cannot delete with limits or offsets");

			if (_where == null && predExpr == null)
				throw new InvalidOperationException ("No condition specified");

			var pred = _where;

			if (predExpr != null && predExpr.NodeType == ExpressionType.Lambda) {
				var lambda = (LambdaExpression)predExpr;
				pred = pred != null ? Expression.AndAlso (pred, lambda.Body) : lambda.Body;
			}

			var args = new List<object> ();
			var cmdText = "delete from \"" + Table.TableName + "\"";
			var w = CompileExpr (pred, args);
			cmdText += " where " + w.CommandText;

			var command = Connection.CreateCommand (cmdText, args.ToArray ());

			int result = command.ExecuteNonQuery ();
			return result;
		}

		/// <summary>
		/// Yields a given number of elements from the query and then skips the remainder.
		/// </summary>
		public TableQuery<T> Take (int n)
		{
			var q = Clone<T> ();
			q._limit = n;
			return q;
		}

		/// <summary>
		/// Skips a given number of elements from the query and then yields the remainder.
		/// </summary>
		public TableQuery<T> Skip (int n)
		{
			var q = Clone<T> ();
			q._offset = n;
			return q;
		}

		/// <summary>
		/// Returns the element at a given index
		/// </summary>
		public T ElementAt (int index)
		{
			return Skip (index).Take (1).First ();
		}

		bool _deferred;
		public TableQuery<T> Deferred ()
		{
			var q = Clone<T> ();
			q._deferred = true;
			return q;
		}

		/// <summary>
		/// Order the query results according to a key.
		/// </summary>
		public TableQuery<T> OrderBy<U> (Expression<Func<T, U>> orderExpr)
		{
			return AddOrderBy<U> (orderExpr, true);
		}

		/// <summary>
		/// Order the query results according to a key.
		/// </summary>
		public TableQuery<T> OrderByDescending<U> (Expression<Func<T, U>> orderExpr)
		{
			return AddOrderBy<U> (orderExpr, false);
		}

		/// <summary>
		/// Order the query results according to a key.
		/// </summary>
		public TableQuery<T> ThenBy<U> (Expression<Func<T, U>> orderExpr)
		{
			return AddOrderBy<U> (orderExpr, true);
		}

		/// <summary>
		/// Order the query results according to a key.
		/// </summary>
		public TableQuery<T> ThenByDescending<U> (Expression<Func<T, U>> orderExpr)
		{
			return AddOrderBy<U> (orderExpr, false);
		}

		TableQuery<T> AddOrderBy<U> (Expression<Func<T, U>> orderExpr, bool asc)
		{
			if (orderExpr.NodeType == ExpressionType.Lambda) {
				var lambda = (LambdaExpression)orderExpr;

				MemberExpression mem = null;

				var unary = lambda.Body as UnaryExpression;
				if (unary != null && unary.NodeType == ExpressionType.Convert) {
					mem = unary.Operand as MemberExpression;
				}
				else {
					mem = lambda.Body as MemberExpression;
				}

				if (mem != null && (mem.Expression.NodeType == ExpressionType.Parameter)) {
					var q = Clone<T> ();
					if (q._orderBys == null) {
						q._orderBys = new List<Ordering> ();
					}
					q._orderBys.Add (new Ordering {
						ColumnName = Table.FindColumnWithPropertyName (mem.Member.Name).Name,
						Ascending = asc
					});
					return q;
				}
				else {
					throw new NotSupportedException ("Order By does not support: " + orderExpr);
				}
			}
			else {
				throw new NotSupportedException ("Must be a predicate");
			}
		}

		private void AddWhere (Expression pred)
		{
			if (_where == null) {
				_where = pred;
			}
			else {
				_where = Expression.AndAlso (_where, pred);
			}
		}

		///// <summary>
		///// Performs an inner join of two queries based on matching keys extracted from the elements.
		///// </summary>
		//public TableQuery<TResult> Join<TInner, TKey, TResult> (
		//	TableQuery<TInner> inner,
		//	Expression<Func<T, TKey>> outerKeySelector,
		//	Expression<Func<TInner, TKey>> innerKeySelector,
		//	Expression<Func<T, TInner, TResult>> resultSelector)
		//{
		//	var q = new TableQuery<TResult> (Connection, Connection.GetMapping (typeof (TResult))) {
		//		_joinOuter = this,
		//		_joinOuterKeySelector = outerKeySelector,
		//		_joinInner = inner,
		//		_joinInnerKeySelector = innerKeySelector,
		//		_joinSelector = resultSelector,
		//	};
		//	return q;
		//}

		// Not needed until Joins are supported
		// Keeping this commented out forces the default Linq to objects processor to run
		//public TableQuery<TResult> Select<TResult> (Expression<Func<T, TResult>> selector)
		//{
		//	var q = Clone<TResult> ();
		//	q._selector = selector;
		//	return q;
		//}

		private SQLiteCommand GenerateCommand (string selectionList)
		{
			if (_joinInner != null && _joinOuter != null) {
				throw new NotSupportedException ("Joins are not supported.");
			}
			else {
				var cmdText = "select " + selectionList + " from \"" + Table.TableName + "\"";
				var args = new List<object> ();
				if (_where != null) {
					var w = CompileExpr (_where, args);
					cmdText += " where " + w.CommandText;
				}
				if ((_orderBys != null) && (_orderBys.Count > 0)) {
					var t = string.Join (", ", _orderBys.Select (o => "\"" + o.ColumnName + "\"" + (o.Ascending ? "" : " desc")).ToArray ());
					cmdText += " order by " + t;
				}
				if (_limit.HasValue) {
					cmdText += " limit " + _limit.Value;
				}
				if (_offset.HasValue) {
					if (!_limit.HasValue) {
						cmdText += " limit -1 ";
					}
					cmdText += " offset " + _offset.Value;
				}
				return Connection.CreateCommand (cmdText, args.ToArray ());
			}
		}

		class CompileResult
		{
			public string CommandText { get; set; }

			public object Value { get; set; }
		}

		private CompileResult CompileExpr (Expression expr, List<object> queryArgs)
		{
			if (expr == null) {
				throw new NotSupportedException ("Expression is NULL");
			}
			else if (expr is BinaryExpression) {
				var bin = (BinaryExpression)expr;

				// VB turns 'x=="foo"' into 'CompareString(x,"foo",true/false)==0', so we need to unwrap it
				// http://blogs.msdn.com/b/vbteam/archive/2007/09/18/vb-expression-trees-string-comparisons.aspx
				if (bin.Left.NodeType == ExpressionType.Call) {
					var call = (MethodCallExpression)bin.Left;
					if (call.Method.DeclaringType.FullName == "Microsoft.VisualBasic.CompilerServices.Operators"
						&& call.Method.Name == "CompareString")
						bin = Expression.MakeBinary (bin.NodeType, call.Arguments[0], call.Arguments[1]);
				}


				var leftr = CompileExpr (bin.Left, queryArgs);
				var rightr = CompileExpr (bin.Right, queryArgs);

				//If either side is a parameter and is null, then handle the other side specially (for "is null"/"is not null")
				string text;
				if (leftr.CommandText == "?" && leftr.Value == null)
					text = CompileNullBinaryExpression (bin, rightr);
				else if (rightr.CommandText == "?" && rightr.Value == null)
					text = CompileNullBinaryExpression (bin, leftr);
				else
					text = "(" + leftr.CommandText + " " + GetSqlName (bin) + " " + rightr.CommandText + ")";
				return new CompileResult { CommandText = text };
			}
			else if (expr.NodeType == ExpressionType.Not) {
				var operandExpr = ((UnaryExpression)expr).Operand;
				var opr = CompileExpr (operandExpr, queryArgs);
				object val = opr.Value;
				if (val is bool)
					val = !((bool)val);
				return new CompileResult {
					CommandText = "NOT(" + opr.CommandText + ")",
					Value = val
				};
			}
			else if (expr.NodeType == ExpressionType.Call) {

				var call = (MethodCallExpression)expr;
				var args = new CompileResult[call.Arguments.Count];
				var obj = call.Object != null ? CompileExpr (call.Object, queryArgs) : null;

				for (var i = 0; i < args.Length; i++) {
					args[i] = CompileExpr (call.Arguments[i], queryArgs);
				}

				var sqlCall = "";

				if (call.Method.Name == "Like" && args.Length == 2) {
					sqlCall = "(" + args[0].CommandText + " like " + args[1].CommandText + ")";
				}
				else if (call.Method.Name == "Contains" && args.Length == 2) {
					sqlCall = "(" + args[1].CommandText + " in " + args[0].CommandText + ")";
				}
				else if (call.Method.Name == "Contains" && args.Length == 1) {
					if (call.Object != null && call.Object.Type == typeof (string)) {
						sqlCall = "( instr(" + obj.CommandText + "," + args[0].CommandText + ") >0 )";
					}
					else {
						sqlCall = "(" + args[0].CommandText + " in " + obj.CommandText + ")";
					}
				}
				else if (call.Method.Name == "StartsWith" && args.Length >= 1) {
					var startsWithCmpOp = StringComparison.CurrentCulture;
					if (args.Length == 2) {
						startsWithCmpOp = (StringComparison)args[1].Value;
					}
					switch (startsWithCmpOp) {
						case StringComparison.Ordinal:
						case StringComparison.CurrentCulture:
							sqlCall = "( substr(" + obj.CommandText + ", 1, " + args[0].Value.ToString ().Length + ") =  " + args[0].CommandText + ")";
							break;
						case StringComparison.OrdinalIgnoreCase:
						case StringComparison.CurrentCultureIgnoreCase:
							sqlCall = "(" + obj.CommandText + " like (" + args[0].CommandText + " || '%'))";
							break;
					}

				}
				else if (call.Method.Name == "EndsWith" && args.Length >= 1) {
					var endsWithCmpOp = StringComparison.CurrentCulture;
					if (args.Length == 2) {
						endsWithCmpOp = (StringComparison)args[1].Value;
					}
					switch (endsWithCmpOp) {
						case StringComparison.Ordinal:
						case StringComparison.CurrentCulture:
							sqlCall = "( substr(" + obj.CommandText + ", length(" + obj.CommandText + ") - " + args[0].Value.ToString ().Length + "+1, " + args[0].Value.ToString ().Length + ") =  " + args[0].CommandText + ")";
							break;
						case StringComparison.OrdinalIgnoreCase:
						case StringComparison.CurrentCultureIgnoreCase:
							sqlCall = "(" + obj.CommandText + " like ('%' || " + args[0].CommandText + "))";
							break;
					}
				}
				else if (call.Method.Name == "Equals" && args.Length == 1) {
					sqlCall = "(" + obj.CommandText + " = (" + args[0].CommandText + "))";
				}
				else if (call.Method.Name == "ToLower") {
					sqlCall = "(lower(" + obj.CommandText + "))";
				}
				else if (call.Method.Name == "ToUpper") {
					sqlCall = "(upper(" + obj.CommandText + "))";
				}
				else if (call.Method.Name == "Replace" && args.Length == 2) {
					sqlCall = "(replace(" + obj.CommandText + "," + args[0].CommandText + "," + args[1].CommandText + "))";
				}
				else {
					sqlCall = call.Method.Name.ToLower () + "(" + string.Join (",", args.Select (a => a.CommandText).ToArray ()) + ")";
				}
				return new CompileResult { CommandText = sqlCall };

			}
			else if (expr.NodeType == ExpressionType.Constant) {
				var c = (ConstantExpression)expr;
				queryArgs.Add (c.Value);
				return new CompileResult {
					CommandText = "?",
					Value = c.Value
				};
			}
			else if (expr.NodeType == ExpressionType.Convert) {
				var u = (UnaryExpression)expr;
				var ty = u.Type;
				var valr = CompileExpr (u.Operand, queryArgs);
				return new CompileResult {
					CommandText = valr.CommandText,
					Value = valr.Value != null ? ConvertTo (valr.Value, ty) : null
				};
			}
			else if (expr.NodeType == ExpressionType.MemberAccess) {
				var mem = (MemberExpression)expr;

				var paramExpr = mem.Expression as ParameterExpression;
				if (paramExpr == null) {
					var convert = mem.Expression as UnaryExpression;
					if (convert != null && convert.NodeType == ExpressionType.Convert) {
						paramExpr = convert.Operand as ParameterExpression;
					}
				}

				if (paramExpr != null) {
					//
					// This is a column of our table, output just the column name
					// Need to translate it if that column name is mapped
					//
					var columnName = Table.FindColumnWithPropertyName (mem.Member.Name).Name;
					return new CompileResult { CommandText = "\"" + columnName + "\"" };
				}
				else {
					object obj = null;
					if (mem.Expression != null) {
						var r = CompileExpr (mem.Expression, queryArgs);
						if (r.Value == null) {
							throw new NotSupportedException ("Member access failed to compile expression");
						}
						if (r.CommandText == "?") {
							queryArgs.RemoveAt (queryArgs.Count - 1);
						}
						obj = r.Value;
					}

					//
					// Get the member value
					//
					object val = null;

					if (mem.Member is PropertyInfo) {
						var m = (PropertyInfo)mem.Member;
						val = m.GetValue (obj, null);
					}
					else if (mem.Member is FieldInfo) {
						var m = (FieldInfo)mem.Member;
						val = m.GetValue (obj);
					}
					else {
						throw new NotSupportedException ("MemberExpr: " + mem.Member.GetType ());
					}

					//
					// Work special magic for enumerables
					//
					if (val != null && val is System.Collections.IEnumerable && !(val is string) && !(val is System.Collections.Generic.IEnumerable<byte>)) {
						var sb = new System.Text.StringBuilder ();
						sb.Append ("(");
						var head = "";
						foreach (var a in (System.Collections.IEnumerable)val) {
							queryArgs.Add (a);
							sb.Append (head);
							sb.Append ("?");
							head = ",";
						}
						sb.Append (")");
						return new CompileResult {
							CommandText = sb.ToString (),
							Value = val
						};
					}
					else {
						queryArgs.Add (val);
						return new CompileResult {
							CommandText = "?",
							Value = val
						};
					}
				}
			}
			throw new NotSupportedException ("Cannot compile: " + expr.NodeType.ToString ());
		}

		static object ConvertTo (object obj, Type t)
		{
			Type nut = Nullable.GetUnderlyingType (t);

			if (nut != null) {
				if (obj == null) return null;
				return Convert.ChangeType (obj, nut);
			}
			else {
				return Convert.ChangeType (obj, t);
			}
		}

		/// <summary>
		/// Compiles a BinaryExpression where one of the parameters is null.
		/// </summary>
		/// <param name="expression">The expression to compile</param>
		/// <param name="parameter">The non-null parameter</param>
		private string CompileNullBinaryExpression (BinaryExpression expression, CompileResult parameter)
		{
			if (expression.NodeType == ExpressionType.Equal)
				return "(" + parameter.CommandText + " is ?)";
			else if (expression.NodeType == ExpressionType.NotEqual)
				return "(" + parameter.CommandText + " is not ?)";
			else if (expression.NodeType == ExpressionType.GreaterThan
				|| expression.NodeType == ExpressionType.GreaterThanOrEqual
				|| expression.NodeType == ExpressionType.LessThan
				|| expression.NodeType == ExpressionType.LessThanOrEqual)
				return "(" + parameter.CommandText + " < ?)"; // always false
			else
				throw new NotSupportedException ("Cannot compile Null-BinaryExpression with type " + expression.NodeType.ToString ());
		}

		string GetSqlName (Expression expr)
		{
			var n = expr.NodeType;
			if (n == ExpressionType.GreaterThan)
				return ">";
			else if (n == ExpressionType.GreaterThanOrEqual) {
				return ">=";
			}
			else if (n == ExpressionType.LessThan) {
				return "<";
			}
			else if (n == ExpressionType.LessThanOrEqual) {
				return "<=";
			}
			else if (n == ExpressionType.And) {
				return "&";
			}
			else if (n == ExpressionType.AndAlso) {
				return "and";
			}
			else if (n == ExpressionType.Or) {
				return "|";
			}
			else if (n == ExpressionType.OrElse) {
				return "or";
			}
			else if (n == ExpressionType.Equal) {
				return "=";
			}
			else if (n == ExpressionType.NotEqual) {
				return "!=";
			}
			else {
				throw new NotSupportedException ("Cannot get SQL for: " + n);
			}
		}

		/// <summary>
		/// Execute SELECT COUNT(*) on the query
		/// </summary>
		public int Count ()
		{
			return GenerateCommand ("count(*)").ExecuteScalar<int> ();
		}

		/// <summary>
		/// Execute SELECT COUNT(*) on the query with an additional WHERE clause.
		/// </summary>
		public int Count (Expression<Func<T, bool>> predExpr)
		{
			return Where (predExpr).Count ();
		}

		public IEnumerator<T> GetEnumerator ()
		{
			if (!_deferred)
				return GenerateCommand ("*").ExecuteQuery<T> ().GetEnumerator ();

			return GenerateCommand ("*").ExecuteDeferredQuery<T> ().GetEnumerator ();
		}

		System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator ()
		{
			return GetEnumerator ();
		}

		/// <summary>
		/// Queries the database and returns the results as a List.
		/// </summary>
		public List<T> ToList ()
		{
			return GenerateCommand ("*").ExecuteQuery<T> ();
		}

		/// <summary>
		/// Queries the database and returns the results as an array.
		/// </summary>
		public T[] ToArray ()
		{
			return GenerateCommand ("*").ExecuteQuery<T> ().ToArray ();
		}

		/// <summary>
		/// Returns the first element of this query.
		/// </summary>
		public T First ()
		{
			var query = Take (1);
			return query.ToList ().First ();
		}

		/// <summary>
		/// Returns the first element of this query, or null if no element is found.
		/// </summary>
		public T FirstOrDefault ()
		{
			var query = Take (1);
			return query.ToList ().FirstOrDefault ();
		}

		/// <summary>
		/// Returns the first element of this query that matches the predicate.
		/// </summary>
		public T First (Expression<Func<T, bool>> predExpr)
		{
			return Where (predExpr).First ();
		}

		/// <summary>
		/// Returns the first element of this query that matches the predicate, or null
		/// if no element is found.
		/// </summary>
		public T FirstOrDefault (Expression<Func<T, bool>> predExpr)
		{
			return Where (predExpr).FirstOrDefault ();
		}
	}

	public static class SQLite3
	{
		public enum Result : int
		{
			OK = 0,
			Error = 1,
			Internal = 2,
			Perm = 3,
			Abort = 4,
			Busy = 5,
			Locked = 6,
			NoMem = 7,
			ReadOnly = 8,
			Interrupt = 9,
			IOError = 10,
			Corrupt = 11,
			NotFound = 12,
			Full = 13,
			CannotOpen = 14,
			LockErr = 15,
			Empty = 16,
			SchemaChngd = 17,
			TooBig = 18,
			Constraint = 19,
			Mismatch = 20,
			Misuse = 21,
			NotImplementedLFS = 22,
			AccessDenied = 23,
			Format = 24,
			Range = 25,
			NonDBFile = 26,
			Notice = 27,
			Warning = 28,
			Row = 100,
			Done = 101
		}

		public enum ExtendedResult : int
		{
			IOErrorRead = (Result.IOError | (1 << 8)),
			IOErrorShortRead = (Result.IOError | (2 << 8)),
			IOErrorWrite = (Result.IOError | (3 << 8)),
			IOErrorFsync = (Result.IOError | (4 << 8)),
			IOErrorDirFSync = (Result.IOError | (5 << 8)),
			IOErrorTruncate = (Result.IOError | (6 << 8)),
			IOErrorFStat = (Result.IOError | (7 << 8)),
			IOErrorUnlock = (Result.IOError | (8 << 8)),
			IOErrorRdlock = (Result.IOError | (9 << 8)),
			IOErrorDelete = (Result.IOError | (10 << 8)),
			IOErrorBlocked = (Result.IOError | (11 << 8)),
			IOErrorNoMem = (Result.IOError | (12 << 8)),
			IOErrorAccess = (Result.IOError | (13 << 8)),
			IOErrorCheckReservedLock = (Result.IOError | (14 << 8)),
			IOErrorLock = (Result.IOError | (15 << 8)),
			IOErrorClose = (Result.IOError | (16 << 8)),
			IOErrorDirClose = (Result.IOError | (17 << 8)),
			IOErrorSHMOpen = (Result.IOError | (18 << 8)),
			IOErrorSHMSize = (Result.IOError | (19 << 8)),
			IOErrorSHMLock = (Result.IOError | (20 << 8)),
			IOErrorSHMMap = (Result.IOError | (21 << 8)),
			IOErrorSeek = (Result.IOError | (22 << 8)),
			IOErrorDeleteNoEnt = (Result.IOError | (23 << 8)),
			IOErrorMMap = (Result.IOError | (24 << 8)),
			LockedSharedcache = (Result.Locked | (1 << 8)),
			BusyRecovery = (Result.Busy | (1 << 8)),
			CannottOpenNoTempDir = (Result.CannotOpen | (1 << 8)),
			CannotOpenIsDir = (Result.CannotOpen | (2 << 8)),
			CannotOpenFullPath = (Result.CannotOpen | (3 << 8)),
			CorruptVTab = (Result.Corrupt | (1 << 8)),
			ReadonlyRecovery = (Result.ReadOnly | (1 << 8)),
			ReadonlyCannotLock = (Result.ReadOnly | (2 << 8)),
			ReadonlyRollback = (Result.ReadOnly | (3 << 8)),
			AbortRollback = (Result.Abort | (2 << 8)),
			ConstraintCheck = (Result.Constraint | (1 << 8)),
			ConstraintCommitHook = (Result.Constraint | (2 << 8)),
			ConstraintForeignKey = (Result.Constraint | (3 << 8)),
			ConstraintFunction = (Result.Constraint | (4 << 8)),
			ConstraintNotNull = (Result.Constraint | (5 << 8)),
			ConstraintPrimaryKey = (Result.Constraint | (6 << 8)),
			ConstraintTrigger = (Result.Constraint | (7 << 8)),
			ConstraintUnique = (Result.Constraint | (8 << 8)),
			ConstraintVTab = (Result.Constraint | (9 << 8)),
			NoticeRecoverWAL = (Result.Notice | (1 << 8)),
			NoticeRecoverRollback = (Result.Notice | (2 << 8))
		}


		public enum ConfigOption : int
		{
			SingleThread = 1,
			MultiThread = 2,
			Serialized = 3
		}

		const string LibraryPath = "sqlite3";

#if !USE_CSHARP_SQLITE && !USE_WP8_NATIVE_SQLITE && !USE_SQLITEPCL_RAW
		[DllImport(LibraryPath, EntryPoint = "sqlite3_threadsafe", CallingConvention=CallingConvention.Cdecl)]
		public static extern int Threadsafe ();

		[DllImport(LibraryPath, EntryPoint = "sqlite3_open", CallingConvention=CallingConvention.Cdecl)]
		public static extern Result Open ([MarshalAs(UnmanagedType.LPStr)] string filename, out IntPtr db);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_open_v2", CallingConvention=CallingConvention.Cdecl)]
		public static extern Result Open ([MarshalAs(UnmanagedType.LPStr)] string filename, out IntPtr db, int flags, [MarshalAs (UnmanagedType.LPStr)] string zvfs);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_open_v2", CallingConvention = CallingConvention.Cdecl)]
		public static extern Result Open(byte[] filename, out IntPtr db, int flags, [MarshalAs (UnmanagedType.LPStr)] string zvfs);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_open16", CallingConvention = CallingConvention.Cdecl)]
		public static extern Result Open16([MarshalAs(UnmanagedType.LPWStr)] string filename, out IntPtr db);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_enable_load_extension", CallingConvention=CallingConvention.Cdecl)]
		public static extern Result EnableLoadExtension (IntPtr db, int onoff);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_close", CallingConvention=CallingConvention.Cdecl)]
		public static extern Result Close (IntPtr db);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_close_v2", CallingConvention = CallingConvention.Cdecl)]
		public static extern Result Close2(IntPtr db);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_initialize", CallingConvention=CallingConvention.Cdecl)]
		public static extern Result Initialize();

		[DllImport(LibraryPath, EntryPoint = "sqlite3_shutdown", CallingConvention=CallingConvention.Cdecl)]
		public static extern Result Shutdown();

		[DllImport(LibraryPath, EntryPoint = "sqlite3_config", CallingConvention=CallingConvention.Cdecl)]
		public static extern Result Config (ConfigOption option);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_win32_set_directory", CallingConvention=CallingConvention.Cdecl, CharSet=CharSet.Unicode)]
		public static extern int SetDirectory (uint directoryType, string directoryPath);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_busy_timeout", CallingConvention=CallingConvention.Cdecl)]
		public static extern Result BusyTimeout (IntPtr db, int milliseconds);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_changes", CallingConvention=CallingConvention.Cdecl)]
		public static extern int Changes (IntPtr db);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_prepare_v2", CallingConvention=CallingConvention.Cdecl)]
		public static extern Result Prepare2 (IntPtr db, [MarshalAs(UnmanagedType.LPStr)] string sql, int numBytes, out IntPtr stmt, IntPtr pzTail);

#if NETFX_CORE
		[DllImport (LibraryPath, EntryPoint = "sqlite3_prepare_v2", CallingConvention = CallingConvention.Cdecl)]
		public static extern Result Prepare2 (IntPtr db, byte[] queryBytes, int numBytes, out IntPtr stmt, IntPtr pzTail);
#endif

		public static IntPtr Prepare2 (IntPtr db, string query)
		{
			IntPtr stmt;
#if NETFX_CORE
            byte[] queryBytes = System.Text.UTF8Encoding.UTF8.GetBytes (query);
            var r = Prepare2 (db, queryBytes, queryBytes.Length, out stmt, IntPtr.Zero);
#else
            var r = Prepare2 (db, query, System.Text.UTF8Encoding.UTF8.GetByteCount (query), out stmt, IntPtr.Zero);
#endif
			if (r != Result.OK) {
				throw SQLiteException.New (r, GetErrmsg (db));
			}
			return stmt;
		}

		[DllImport(LibraryPath, EntryPoint = "sqlite3_step", CallingConvention=CallingConvention.Cdecl)]
		public static extern Result Step (IntPtr stmt);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_reset", CallingConvention=CallingConvention.Cdecl)]
		public static extern Result Reset (IntPtr stmt);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_finalize", CallingConvention=CallingConvention.Cdecl)]
		public static extern Result Finalize (IntPtr stmt);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_last_insert_rowid", CallingConvention=CallingConvention.Cdecl)]
		public static extern long LastInsertRowid (IntPtr db);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_errmsg16", CallingConvention=CallingConvention.Cdecl)]
		public static extern IntPtr Errmsg (IntPtr db);

		public static string GetErrmsg (IntPtr db)
		{
			return Marshal.PtrToStringUni (Errmsg (db));
		}

		[DllImport(LibraryPath, EntryPoint = "sqlite3_bind_parameter_index", CallingConvention=CallingConvention.Cdecl)]
		public static extern int BindParameterIndex (IntPtr stmt, [MarshalAs(UnmanagedType.LPStr)] string name);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_bind_null", CallingConvention=CallingConvention.Cdecl)]
		public static extern int BindNull (IntPtr stmt, int index);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_bind_int", CallingConvention=CallingConvention.Cdecl)]
		public static extern int BindInt (IntPtr stmt, int index, int val);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_bind_int64", CallingConvention=CallingConvention.Cdecl)]
		public static extern int BindInt64 (IntPtr stmt, int index, long val);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_bind_double", CallingConvention=CallingConvention.Cdecl)]
		public static extern int BindDouble (IntPtr stmt, int index, double val);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_bind_text16", CallingConvention=CallingConvention.Cdecl, CharSet = CharSet.Unicode)]
		public static extern int BindText (IntPtr stmt, int index, [MarshalAs(UnmanagedType.LPWStr)] string val, int n, IntPtr free);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_bind_blob", CallingConvention=CallingConvention.Cdecl)]
		public static extern int BindBlob (IntPtr stmt, int index, byte[] val, int n, IntPtr free);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_column_count", CallingConvention=CallingConvention.Cdecl)]
		public static extern int ColumnCount (IntPtr stmt);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_column_name", CallingConvention=CallingConvention.Cdecl)]
		public static extern IntPtr ColumnName (IntPtr stmt, int index);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_column_name16", CallingConvention=CallingConvention.Cdecl)]
		static extern IntPtr ColumnName16Internal (IntPtr stmt, int index);
		public static string ColumnName16(IntPtr stmt, int index)
		{
			return Marshal.PtrToStringUni(ColumnName16Internal(stmt, index));
		}

		[DllImport(LibraryPath, EntryPoint = "sqlite3_column_type", CallingConvention=CallingConvention.Cdecl)]
		public static extern ColType ColumnType (IntPtr stmt, int index);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_column_int", CallingConvention=CallingConvention.Cdecl)]
		public static extern int ColumnInt (IntPtr stmt, int index);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_column_int64", CallingConvention=CallingConvention.Cdecl)]
		public static extern long ColumnInt64 (IntPtr stmt, int index);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_column_double", CallingConvention=CallingConvention.Cdecl)]
		public static extern double ColumnDouble (IntPtr stmt, int index);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_column_text", CallingConvention=CallingConvention.Cdecl)]
		public static extern IntPtr ColumnText (IntPtr stmt, int index);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_column_text16", CallingConvention=CallingConvention.Cdecl)]
		public static extern IntPtr ColumnText16 (IntPtr stmt, int index);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_column_blob", CallingConvention=CallingConvention.Cdecl)]
		public static extern IntPtr ColumnBlob (IntPtr stmt, int index);

		[DllImport(LibraryPath, EntryPoint = "sqlite3_column_bytes", CallingConvention=CallingConvention.Cdecl)]
		public static extern int ColumnBytes (IntPtr stmt, int index);

		public static string ColumnString (IntPtr stmt, int index)
		{
			return Marshal.PtrToStringUni (SQLite3.ColumnText16 (stmt, index));
		}

		public static byte[] ColumnByteArray (IntPtr stmt, int index)
		{
			int length = ColumnBytes (stmt, index);
			var result = new byte[length];
			if (length > 0)
				Marshal.Copy (ColumnBlob (stmt, index), result, 0, length);
			return result;
		}

		[DllImport (LibraryPath, EntryPoint = "sqlite3_errcode", CallingConvention = CallingConvention.Cdecl)]
		public static extern Result GetResult (Sqlite3DatabaseHandle db);

		[DllImport (LibraryPath, EntryPoint = "sqlite3_extended_errcode", CallingConvention = CallingConvention.Cdecl)]
		public static extern ExtendedResult ExtendedErrCode (IntPtr db);

		[DllImport (LibraryPath, EntryPoint = "sqlite3_libversion_number", CallingConvention = CallingConvention.Cdecl)]
		public static extern int LibVersionNumber ();

		[DllImport (LibraryPath, EntryPoint = "sqlite3_backup_init", CallingConvention = CallingConvention.Cdecl)]
		public static extern Sqlite3BackupHandle BackupInit (Sqlite3DatabaseHandle destDb, [MarshalAs (UnmanagedType.LPStr)] string destName, Sqlite3DatabaseHandle sourceDb, [MarshalAs (UnmanagedType.LPStr)] string sourceName);

		[DllImport (LibraryPath, EntryPoint = "sqlite3_backup_step", CallingConvention = CallingConvention.Cdecl)]
		public static extern Result BackupStep (Sqlite3BackupHandle backup, int numPages);

		[DllImport (LibraryPath, EntryPoint = "sqlite3_backup_finish", CallingConvention = CallingConvention.Cdecl)]
		public static extern Result BackupFinish (Sqlite3BackupHandle backup);
#else
		public static Result Open (string filename, out Sqlite3DatabaseHandle db)
		{
			return (Result)Sqlite3.sqlite3_open (filename, out db);
		}

		public static Result Open (string filename, out Sqlite3DatabaseHandle db, int flags, string vfsName)
		{
#if USE_WP8_NATIVE_SQLITE
			return (Result)Sqlite3.sqlite3_open_v2(filename, out db, flags, vfsName ?? "");
#else
			return (Result)Sqlite3.sqlite3_open_v2 (filename, out db, flags, vfsName);
#endif
		}

		public static Result Close (Sqlite3DatabaseHandle db)
		{
			return (Result)Sqlite3.sqlite3_close (db);
		}

		public static Result Close2 (Sqlite3DatabaseHandle db)
		{
			return (Result)Sqlite3.sqlite3_close_v2 (db);
		}

		public static Result BusyTimeout (Sqlite3DatabaseHandle db, int milliseconds)
		{
			return (Result)Sqlite3.sqlite3_busy_timeout (db, milliseconds);
		}

		public static int Changes (Sqlite3DatabaseHandle db)
		{
			return Sqlite3.sqlite3_changes (db);
		}

		public static Sqlite3Statement Prepare2 (Sqlite3DatabaseHandle db, string query)
		{
			Sqlite3Statement stmt = default (Sqlite3Statement);
#if USE_WP8_NATIVE_SQLITE || USE_SQLITEPCL_RAW
			var r = Sqlite3.sqlite3_prepare_v2 (db, query, out stmt);
#else
			stmt = new Sqlite3Statement();
			var r = Sqlite3.sqlite3_prepare_v2(db, query, -1, ref stmt, 0);
#endif
			if (r != 0) {
				throw SQLiteException.New ((Result)r, GetErrmsg (db));
			}
			return stmt;
		}

		public static Result Step (Sqlite3Statement stmt)
		{
			return (Result)Sqlite3.sqlite3_step (stmt);
		}

		public static Result Reset (Sqlite3Statement stmt)
		{
			return (Result)Sqlite3.sqlite3_reset (stmt);
		}

		public static Result Finalize (Sqlite3Statement stmt)
		{
			return (Result)Sqlite3.sqlite3_finalize (stmt);
		}

		public static long LastInsertRowid (Sqlite3DatabaseHandle db)
		{
			return Sqlite3.sqlite3_last_insert_rowid (db);
		}

		public static string GetErrmsg (Sqlite3DatabaseHandle db)
		{
			return Sqlite3.sqlite3_errmsg (db).utf8_to_string();
		}

		public static int BindParameterIndex (Sqlite3Statement stmt, string name)
		{
			return Sqlite3.sqlite3_bind_parameter_index (stmt, name);
		}

		public static int BindNull (Sqlite3Statement stmt, int index)
		{
			return Sqlite3.sqlite3_bind_null (stmt, index);
		}

		public static int BindInt (Sqlite3Statement stmt, int index, int val)
		{
			return Sqlite3.sqlite3_bind_int (stmt, index, val);
		}

		public static int BindInt64 (Sqlite3Statement stmt, int index, long val)
		{
			return Sqlite3.sqlite3_bind_int64 (stmt, index, val);
		}

		public static int BindDouble (Sqlite3Statement stmt, int index, double val)
		{
			return Sqlite3.sqlite3_bind_double (stmt, index, val);
		}

		public static int BindText (Sqlite3Statement stmt, int index, string val, int n, IntPtr free)
		{
#if USE_WP8_NATIVE_SQLITE
			return Sqlite3.sqlite3_bind_text(stmt, index, val, n);
#elif USE_SQLITEPCL_RAW
			return Sqlite3.sqlite3_bind_text (stmt, index, val);
#else
			return Sqlite3.sqlite3_bind_text(stmt, index, val, n, null);
#endif
		}

		public static int BindBlob (Sqlite3Statement stmt, int index, byte[] val, int n, IntPtr free)
		{
#if USE_WP8_NATIVE_SQLITE
			return Sqlite3.sqlite3_bind_blob(stmt, index, val, n);
#elif USE_SQLITEPCL_RAW
			return Sqlite3.sqlite3_bind_blob (stmt, index, val);
#else
			return Sqlite3.sqlite3_bind_blob(stmt, index, val, n, null);
#endif
		}

		public static int ColumnCount (Sqlite3Statement stmt)
		{
			return Sqlite3.sqlite3_column_count (stmt);
		}

		public static string ColumnName (Sqlite3Statement stmt, int index)
		{
			return Sqlite3.sqlite3_column_name (stmt, index).utf8_to_string ();
		}

		public static string ColumnName16 (Sqlite3Statement stmt, int index)
		{
			return Sqlite3.sqlite3_column_name (stmt, index).utf8_to_string ();
		}

		public static ColType ColumnType (Sqlite3Statement stmt, int index)
		{
			return (ColType)Sqlite3.sqlite3_column_type (stmt, index);
		}

		public static int ColumnInt (Sqlite3Statement stmt, int index)
		{
			return Sqlite3.sqlite3_column_int (stmt, index);
		}

		public static long ColumnInt64 (Sqlite3Statement stmt, int index)
		{
			return Sqlite3.sqlite3_column_int64 (stmt, index);
		}

		public static double ColumnDouble (Sqlite3Statement stmt, int index)
		{
			return Sqlite3.sqlite3_column_double (stmt, index);
		}

		public static string ColumnText (Sqlite3Statement stmt, int index)
		{
			return Sqlite3.sqlite3_column_text (stmt, index).utf8_to_string ();
		}

		public static string ColumnText16 (Sqlite3Statement stmt, int index)
		{
			return Sqlite3.sqlite3_column_text (stmt, index).utf8_to_string ();
		}

		public static byte[] ColumnBlob (Sqlite3Statement stmt, int index)
		{
			return Sqlite3.sqlite3_column_blob (stmt, index).ToArray ();
		}

		public static int ColumnBytes (Sqlite3Statement stmt, int index)
		{
			return Sqlite3.sqlite3_column_bytes (stmt, index);
		}

		public static string ColumnString (Sqlite3Statement stmt, int index)
		{
			return Sqlite3.sqlite3_column_text (stmt, index).utf8_to_string ();
		}

		public static byte[] ColumnByteArray (Sqlite3Statement stmt, int index)
		{
			int length = ColumnBytes (stmt, index);
			if (length > 0) {
				return ColumnBlob (stmt, index);
			}
			return new byte[0];
		}

		public static Result EnableLoadExtension (Sqlite3DatabaseHandle db, int onoff)
		{
			return (Result)Sqlite3.sqlite3_enable_load_extension (db, onoff);
		}

		public static int LibVersionNumber ()
		{
			return Sqlite3.sqlite3_libversion_number ();
		}

		public static Result GetResult (Sqlite3DatabaseHandle db)
		{
			return (Result)Sqlite3.sqlite3_errcode (db);
		}

		public static ExtendedResult ExtendedErrCode (Sqlite3DatabaseHandle db)
		{
			return (ExtendedResult)Sqlite3.sqlite3_extended_errcode (db);
		}

		public static Sqlite3BackupHandle BackupInit (Sqlite3DatabaseHandle destDb, string destName, Sqlite3DatabaseHandle sourceDb, string sourceName)
		{
			return Sqlite3.sqlite3_backup_init (destDb, destName, sourceDb, sourceName);
		}

		public static Result BackupStep (Sqlite3BackupHandle backup, int numPages)
		{
			return (Result)Sqlite3.sqlite3_backup_step (backup, numPages);
		}

		public static Result BackupFinish (Sqlite3BackupHandle backup)
		{
			return (Result)Sqlite3.sqlite3_backup_finish (backup);
		}
#endif

		public enum ColType : int
		{
			Integer = 1,
			Float = 2,
			Text = 3,
			Blob = 4,
			Null = 5
		}
	}
}