NHibernate.Custom.XmlType.cs

/* 
 * UserType allowing easy saving of NHIbernate XmlDocument property.
 *
 * Example
 * =======
 * 
 * //Message.cs - Example class with a XmlDocument
 * public class Message
 * {
 *    public XmlDocument Body{get;set;}
 * }
 *
 * //Message.hbm.xml - The mapping
 * <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
 *   <class name="Message">
 *     <property name="Body" type="NHibernate.Custom.XmlType, NHibernate.Custom" />
 *   </class>
 * </hibernate-mapping>
 *
 * History
 * ======= 
 * - This code was found online somewhere, sorry, I can't remember where :-( 
 * - I've tweaked it a little to work with 2nd level cache and NHibernate 2.1.x. 
 * - Tobin Harris
 */
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Common;
using System.Text;
using System.Xml;
using NHibernate.SqlTypes;
using NHibernate.UserTypes;

namespace NHibernate.Custom
{
	public class XmlType : IUserType
	{
	    public new bool Equals(object x, object y)
	    {
	        if (x == null || y == null)
	            return false;

	        var xdoc_x = (XmlDocument) x;
	        var xdoc_y = (XmlDocument) y;
	        return xdoc_y.OuterXml == xdoc_x.OuterXml;
	    }

	    public int GetHashCode(object x)
	    {
	        return x.GetHashCode();
	    }


	    public object NullSafeGet(IDataReader rs, string[] names, object owner)
	    {
	        if (names.Length != 1)
	            throw new InvalidOperationException("names array has more than one element. can't handle this!");
        
	        var document = new XmlDocument();
        
	        var val = rs[names[0]] as string;
        
	        if (val != null)
	        {
	            document.LoadXml(val);
	            return document;
	        }

	        return null;
	    }

	    public void NullSafeSet(IDbCommand cmd, object value, int index)
	    {
	        var parameter = (DbParameter )cmd.Parameters[index];
        
	        if(value == null)
	        {
	            parameter.Value = DBNull.Value;
	            return;
	        }
        
	        parameter.Value = ((XmlDocument) value).OuterXml;
	    }

	    public object DeepCopy(object value)
	    {
        
	        var toCopy = value as XmlDocument;
        
	        if(toCopy==null)
	            return null;

	        var copy = new XmlDocument();
	        copy.LoadXml(toCopy.OuterXml);
	        return copy;
	    }

	    public object Replace(object original, object target, object owner)
	    {
	        throw new NotImplementedException();
	    }

	    public object Assemble(object cached, object owner)
	    {
	        var str = cached as string;
	        if (str != null)
	        {
	            var doc = new XmlDocument();
	            doc.LoadXml(str);
	            return doc;
	        }
	        else
	        {
	            return null;
	        }

	    }

	    public object Disassemble(object value)
	    {
	        var val = value as XmlDocument;
	        if(val != null)
	        {
	            return val.OuterXml;
	        }
	        else
	        {
	            return null;
	        }
	    }

	    public SqlType[] SqlTypes
	    {
	        get 
	        {
	            return new SqlType[] { new SqlXmlStringType() };
	        }
	    }

	    public Type ReturnedType
	    {
	        get { return typeof(XmlDocument); }
	    }

	    public bool IsMutable
	    {
	        get { return true; }
	    }
	}

	public class SqlXmlType : SqlType
	{
	    public SqlXmlType() : base(DbType.Xml)
	    {
	    }
	}

	public class SqlXmlStringType : SqlType
	{
	    public SqlXmlStringType()
	        : base(DbType.String, 4000)
	    {
	    }     
	}

}

Works like a charm! Ta

You're welcome!

Hi,

I just wanted know while reading the XML data back from DB how we can read it? Most of the examples I went through having talked about only saving the XML document but not the reading back! Can you please give some note on that?

NHibernate and this extension sucks in the XML from the DB and drops it into an XML document. You can then read the XML from there, using XPath or traversing nodes to get at particular bits. Is this what you mean?

Hi,
I need your help on this issue. i am trying NHibarnate mapping to DB2 table which has a column with datatype "XML". I followes the ame approach but getting error "Unknown SQL type - -370". on detail stack trace i got eoor starting from "NullSafeGet(IDataReader rs, String[] names, Object owner)" function. on "var val = rs[names[0]] as string;" line.

can anyone help me out please....