Fix DbType.Guid type registration

Author: hazzik

src/NHibernate/Dialect/DB2Dialect.cs

@@ -55,6 +55,7 @@ public DB2Dialect()
 			RegisterColumnType(DbType.String, 8000, "VARCHAR($l)");
 			RegisterColumnType(DbType.String, 2147483647, "CLOB");
 			RegisterColumnType(DbType.Time, "TIME");
+			RegisterColumnType(DbType.Guid, "CHAR(16) FOR BIT DATA");
 
 			RegisterFunction("abs", new StandardSQLFunction("abs"));
 			RegisterFunction("absval", new StandardSQLFunction("absval"));

src/NHibernate/Driver/DB2DriverBase.cs

@@ -2,6 +2,7 @@
 using System.Data;
 using System.Data.Common;
 using NHibernate.Engine;
+using NHibernate.SqlTypes;
 
 namespace NHibernate.Driver
 {
@@ -47,7 +48,15 @@ public override IResultSetsCommand GetResultSetsCommand(ISessionImplementor sess
 
 		protected override void InitializeParameter(DbParameter dbParam, string name, SqlType sqlType)
 		{
-			dbParam.DbType = sqlType.DbType;
+			switch (sqlType.DbType)
+			{
+				case DbType.Guid:
+					dbParam.DbType = DbType.Binary;
+					break;
+				default:
+					dbParam.DbType = sqlType.DbType;
+					break;
+			}
 		}
 	}
 }