ODP.net Oracle Decimal Number precision problem when filling a dataset. Exception: Arithmetic operation resulted in an overflow

Question

I am working in c# .net 2 (Visual Studio 2005 SP1) attempting to fill a dataset with the results from a select * from table from an Oracle10g database. The .net framework, IDE and database cannot be changed at this client site.

I'm connecting using the ODP.net provider the dll version is 2.102.2.20

When I run the fill command I get an Exception:

Arithmetic operation resulted in an overflow

Also if I attempt to view the offending column in the Visual Studio designer (Show Table Data) I get for every row for this column in the table. The code works perfectly if my query selects other columns with integers for example omitting this column.

The column in question looks fine when I view it in the database from Toad, data looks like:

919.742866695572

I need the precision as it's required for a monte carlo simulation.

If instead of using a data adapter to fill the datatable I use a datareader and call dataReader.getValue(columnIndex) I get the same error but if I call dataReader.GetOracleDecimal(columnIndex) then I get the result I am looking for, no error.

I would rather use data adapter and filling a dataset (note these are untyped datasets as I couldn't get autogenerated strongly typed datasets to work from an oracle db). I don't want to use datareader and walk through the results (pick out the column values) as I am trying to write this as a generic method to work for many scenarios regardless of number of columns, index of decimal columns that would require specific get calls by datatype.

Can anyone help? Can I use new versions of the ODP.net dlls to connect to the older Oracle10g database? am wondering if this will help.

Thanks

Answer 1

You can try the latest version of ODP.Net (11g). It is backwards compatible. I use it to connect to a 10g database just fine. I think it should work with VS 2005 too. For clickonce deployment, just add the dlls referenced by this question: What is the minimum client footprint required to connect C# to an Oracle database? An important note is that if you have the latest version of odp.net, all of the dlls are included in the install directory. You don't need to download instant client separately. Just search for them.

Answer 2

I posted this on the Oracle forums the answer is to use SafeTypeMapping

Answer here: oracle forum post