For calculation, decimal is more appropriate in .NET code. The Oracle driver are a bit messed in .NET world. The unit test have been done against an Oracle Database by Roberto. As I see, a .NET decimal type is map to a number in oracle.
The dbType are different if you used the MS or Oracle driver. You can look at configuration LineIntem.xml file (property Price, column LINEITEM_PRICE) for Oracle driver at http://svn.apache.org/repos/asf/ibatis/trunk/cs/mapper/IBatisNet.DataMapper.Test/Maps/Oracle/OracleClient/ for MS Driver at http://svn.apache.org/repos/asf/ibatis/trunk/cs/mapper/IBatisNet.DataMapper.Test/Maps/Oracle/ODP/ -- Cheers, Gilles <a href="http://www.amazon.com/gp/registry/6JCP7AORB0LE">Wish List</a>

