Thanks Martijn!



At 10:47 AM 21/10/2003 +0200, you wrote:

>Hi Tim,
>
> > :-) I already make extensive use of domains with check constraints - the
> > primary table has every field except the primary key field as a domain
>with
> > a check constraint.
> >
> > As I said, the problem isn't the Inserts so much as the deletes. In the
> > case of a tax table (we also have three here), how do I prevent the user
> > from deleting a tax type if there are any records in the primary table
>with
> > that tax type?
>
>In a BEFORE DELETE trigger, check to see if there are any rows - in all
>child tables!! - with that particular value. Raise an EXCEPTION and the
>DELETE will be aborted.
>
>
>With regards,
>
>Martijn Tonies
>Database Workbench - developer tool for InterBase, Firebird & MS SQL Server.
>Upscene Productions
><http://www.upscene.com>http://www.upscene.com
>
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