Thanks
MoonWaYou can take a look at <a href="http://links.10026.com/?link=http://msdn2.microsoft.com/ms187752.aspx">this</a>.And John Bell wrote a nice text on the microsoft.public.sqlserver.programming newsgroep:
DataTypes - UDTs, the XML data type, and "MAX" BLOBs and CLOBs SQL Server 2005 adds support for user-defined types, a native XML data type and better large data support. Large data support is improved by using the Transact-SQL types VARCHAR(MAX), NVARCHAR(MAX) and VARBINARY(MAX). User-defined types and a native XML type are defined by the SQL:1999 and SQL:2003 specifications. To use these data types with SqlClient, new classes in the System.Data.SqlTypes namespace are defined (SqlUdt and SqlXml), support is added to the SqlDbTypes enumeration and IDataReader.GetValue was enhanced to support returning UDTs as .NET Object types, and support returning XML as a .NET String. These new SQL Server 2005 types are supported in DataReaders returned from SQL SELECT statements and as Parameters using SqlParameter. A special class, SqlMetaData, can return information about extended properties of these new data types, such as the XML schema collection that a strongly typed XML column adheres to, or the database name of a UDT. You can use these types from the client directly, in generic code, and also in the DataSet. Finally you can perform partial updates on the "MAX" data types from the client, which required using special SQL functions before ADO.NET 2.0.
