Oracle Dialect support for Unsigned Int (UInt32, UInt64)

The Oracle9Dialect and OracleDataClientDriver do not support Unsigned ints

This can be fixed by registering the appropriate column types:
This will allow the schema export to succeed.

public class Oracle9Dialect : Dialect
{
public Oracle9Dialect()
{
RegisterColumnType(DbType.UInt16, "NUMBER(5,0)");
RegisterColumnType(DbType.UInt32, "NUMBER(10,0)");
RegisterColumnType(DbType.UInt64, "NUMBER(20,0)");
...

Getting the values back to NHibernate also requires the OracleDataClientDriver to be modified,
Don't know how this code will fit into the codebase with a dependency on Oracle.DataAccess..

protected override void InitializeParameter(IDbDataParameter dbParam, string name, SqlType sqlType)
{
//more information about mapping to native oracle types:
//http://download-uk.oracle.com/docs/cd/B19306_01/win.102/b14306/appendixa.htm#BEHJHHJG

OracleDbType oraType;
if(sqlType.DbType == DbType.UInt16)
{
oraType = OracleDbType.Decimal;
}
else if(sqlType.DbType == DbType.UInt32)
{
oraType = OracleDbType.Decimal;
}
else if(sqlType.DbType == DbType.UInt64)
{
oraType = OracleDbType.Decimal;
}
else if(sqlType.DbType == DbType.Int64)
{
oraType = OracleDbType.Decimal;
}
else if(sqlType.DbType == DbType.DateTime)
{
oraType = OracleDbType.TimeStamp;
}
else
{
//Let the base driver class in NHibernate handle the parameter initialisation
base.InitializeParameter(dbParam, name, sqlType);
return;
}

dbParam.ParameterName = FormatNameForParameter(name);
((OracleParameter)dbParam).OracleDbType = oraType;
...