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Stewart Bourke · Guest

I am looking for general opinions from anybody who has used dbExpress to
support multiple database engines successfully. Although dbExpress only
technically requires the change of a connection string, there are always
issues to do with things like datatypes (especially when it comes to things
like date/datetime/timestamp fields) or sql dialects.

For example, if I wanted to support Interbase, Firebird, Informix and DB2 -
given that dbExpress has driver for all these - if anybody has had any
actual experience in implementing engines that support multiple databases I
would be very interested. I would also be very interested in any feedback
there would be about using things like DataAbstract from RemObjects (or any
other such platforms for introducing database independence).

Any feedback etc would be very much appreciated.

Thanks,

Stewart Bourke

Thomas Miller · Guest

You will need to use dbExpressPlus.

Stewart Bourke wrote:

Jan Doggen · Guest

Hello Stewart

I have a large app that handles either an Oracle or MSSQL datamart. I has a
smaller companion app that reads MSSQL, Oracle, and DB2. That certainly is
do-able.

There were some specific dbExpress issues that I ran across like handling
Integer and BCD persistent fields. Also there's (always) the non-DbExpress
specific stuff like how does the app handle NULLs, there are different
non-compatible field types (I love the DB2 'FOR BIT DATA' fields - not!). I
have no experience with recent versions of Interbase/Firebird.

Transactions are a PITA. I later tried to write them into the app, but threw
them out again, because of two reasons (both not dbExpress issues):
- MSSQL server (the OLEDB provider) has trouble when you're using
forward-only cursors as well as bidirectional one
- Oracle can't mix DDL and DML statement

Bye
Jan

"Stewart Bourke" <stewartbourke_nospam_at_eircom.net> wrote