Nando,

> M> Ann, Helen, can someone help? :-)
>
> this thread already contains all the help you might need on the
> subject. :-) Either you run in the context of the system transaction
> or you are subject to these kinds of inconsistencies.

I still have to disagree --

With a CHECK constaint, I think you SHOULD be able to
do this.

Constraints are the best understanding of your data that the
engine can get. It should be able to enforce those constraints
to keep your data consistent.

Perhaps this is one of those that needs a "deferred" constraint?

With regards,

Martijn Tonies
Database Workbench - developer tool for InterBase, Firebird, MySQL & MS SQL
Server.
Upscene Productions
http://www.upscene.com