Re: cross-table unique constraint

So how might I go about doing this.

3 tables: a, b, and c

When these 3 tables are joined, there is a combination of 3 fields, one
field from each table, that should be unique.

Should there be a trigger that checks this condition on inserts/updates
on each of these tables?

Randall

Bruno Wolff III wrote:
> On Tue, Jan 06, 2004 at 07:10:28 +0000,
> Randall Smith <randall(at)tnr(dot)cc> wrote:
>
>>Is it possible to create a unique constraint on multiple fields in
>>related tables?
>
>
> Not with the normal UNIQUE constraint. That will do multiple columns in
> one table, but won't span tables.
>
> You can probably do what you want using triggers.
>
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