ORA-01790 error in version 5.25.49 and above

marc.wuergler · Post by **marc.wuergler** » Tue 03 Nov 2009 11:34

Hello!

I have been using devart dotconnect for a while now and it usually works quite well.

I have recently updated from version 5.25.42 to version 5.25.49. Since then, my application does not work anymore. On most of my queries, I get the following error:

"ORA-01790: expression must have same datatype as corresponding expression"

I have also tried to use your new version (beta) 5.35, but I get the same error. Moving back to the version 5.25.42 works fine. I am using the entity framework.

In one of your posts, I have found a similar problem (same ora error), but the trick there was to set the Devart.Data.Oracle.Entity.OracleEntityProviderServices.TypedNulls to true. I tried this which made my application start, but every thing became very, very slow and unusable...

Please help me out...

Thanks a lot.

Shalex · Post by **Shalex** » Wed 04 Nov 2009 14:07

We will investigate the issue and notify you about the results as soon as possible.

aldare · Post by **aldare** » Mon 14 Dec 2009 14:49

The same problem here with the new version. Have you found the solution? Thank you

Shalex · Post by **Shalex** » Tue 15 Dec 2009 08:11

Aldare, if you are getting the "ORA-01790: expression must have same datatype as corresponding expression" error, please set Devart.Data.Oracle.Entity.OracleEntityProviderServices.TypedNulls to true.

aldare · Post by **aldare** » Tue 15 Dec 2009 08:47

This solves the problem. Thanks a lot!

Shalex · Post by **Shalex** » Thu 13 Oct 2011 07:59

Starting from the 6.30 version of dotConnect for Oracle, the problems with usage of different combinations of text columns with different code tables are solved successfully. The TypedNulls workaround is not relevant now.

All NULLs are always typed in 6.30 and later versions. This allows to use a complicated query and almost doesn't affect performance.