The Worlds Smallest ORM For People Who Hate ORM's

pooORM.cs

public class DAOBase
{
    private readonly string _connectionString;

    public DAOBase(string database)
    {
        try
        {
            _connectionString = ConfigurationManager.ConnectionStrings[database].ConnectionString;
        }
        catch (Exception ex)
        {
            throw new ApplicationException(String.Format("Error getting connection string {0} from config: {1}", database, ex.Message));
        }
    }

    protected void ExecuteNonQuerySproc(string sprocName, params SqlParameter[] args)
    {
        try
        {
            using (var conn = new SqlConnection(_connectionString))
            {
                using (var cmd = new SqlCommand(sprocName))
                {
                    cmd.Connection = conn;
                    cmd.CommandType = System.Data.CommandType.StoredProcedure;

                    foreach (var arg in args)
                    {
                        cmd.Parameters.Add(arg);
                    }

                    conn.Open();
                    cmd.ExecuteNonQuery();
                }
            }
        }
        catch (Exception ex)
        {
            throw new ApplicationException("Error executing non query stored procedure: " + ex.Message);
        }
    }

    protected IList<T> ExecuteEntitySproc<T>(string sprocName, params SqlParameter[] args) where T : Entity, new()
    {
        try
        {
            using (var conn = new SqlConnection(_connectionString))
            {
                using (var cmd = new SqlCommand(sprocName))
                {
                    cmd.Connection = conn;
                    cmd.CommandType = System.Data.CommandType.StoredProcedure;

                    foreach (var arg in args)
                    {
                        cmd.Parameters.Add(arg);
                    }

                    var ds = new DataSet();
                    using (var da = new SqlDataAdapter() { SelectCommand = cmd })
                    {
                        conn.Open();
                        da.Fill(ds, "results");

                        var entities = new List<T>();
                        foreach (DataRow row in ds.Tables["result"].Rows)
                        {
                            var entity = new T();
                            entity.PopulateFromDataRow(row);
                        }

                        return entities;
                    }
                }
            }
        }
        catch (Exception ex)
        {
            throw new ApplicationException("Error executing query stored procedure: " + ex.Message);
        }
    }

    protected void ExecuteSaveSproc(Entity e, string sprocName, params SqlParameter[] args)
    {
        try
        {
            using (var conn = new SqlConnection(_connectionString))
            {
                using (var cmd = new SqlCommand(sprocName))
                {
                    cmd.Connection = conn;
                    cmd.CommandType = System.Data.CommandType.StoredProcedure;

                    var id = new SqlParameter("id", SqlDbType.Int) { 
                        Direction = ParameterDirection.InputOutput,
                        Value = e.Id
                    };
                    cmd.Parameters.Add(id);
                    foreach (var arg in args)
                    {
                        cmd.Parameters.Add(arg);
                    }

                    conn.Open();
                    cmd.ExecuteNonQuery();

                    if (id.Value != DBNull.Value)
                    {
                        e.Id = Convert.ToInt32(id.Value);
                    }
                }
            }
        }
        catch (Exception ex)
        {
            throw new ApplicationException("Error executing non query stored procedure: " + ex.Message);
        }
    }

    protected DataTable ExecuteDataTableSproc<T>(string sprocName, params SqlParameter[] args) where T : Entity, new()
    {
        try
        {
            using (var conn = new SqlConnection(_connectionString))
            {
                using (var cmd = new SqlCommand(sprocName))
                {
                    cmd.Connection = conn;
                    cmd.CommandType = System.Data.CommandType.StoredProcedure;

                    foreach (var arg in args)
                    {
                        cmd.Parameters.Add(arg);
                    }

                    var ds = new DataSet();
                    using (var da = new SqlDataAdapter() { SelectCommand = cmd })
                    {
                        conn.Open();

                        da.Fill(ds, "results");

                        return ds.Tables["result"];
                    }
                }
            }
        }
        catch (Exception ex)
        {
            throw new ApplicationException("Error getting data table: " + ex.Message);
        }
    }
}

public abstract class Entity
{
    abstract public void PopulateFromDataRow(DataRow row);
    
    public int Id { get; set; }

    protected int GetInt(DataRow row, string column)
    {
        try
        {
            return Convert.ToInt32(row[column].ToString());
        }
        catch (Exception ex)
        {
            throw new ApplicationException(String.Format("Couldn't convert {0} to an integer: {1}", column, ex.Message));
        }
    }

    protected string GetString(DataRow row, string column)
    {
        try
        {
            return row[column].ToString();
        }
        catch (Exception ex)
        {
            throw new ApplicationException(String.Format("Couldn't get {0} from data row: {1}", column, ex.Message));
        }
    }
}

/****************************************************************/
/*                      EXAMPLES                                */
/****************************************************************/

public class Customer : Entity
{
    private int _id;
    private string _name;

    public int Id { get { return _id; } }
    public string Name { get { return _name; } }

    public override void PopulateFromDataRow(DataRow row)
    {
        _id = GetInt(row, "id");
        _name = GetString(row, "name");
    }
}

public class CustomerDAO : DAOBase
{
    public CustomerDAO(string database)
        : base(database)
    {
        
    }

    public IList<Customer> GetCustomers()
    {
        return ExecuteEntitySproc<Customer>("usp_GetAllCustomers");
    }
}