Re: Mandatory on one side of one to many?

From: Mike MacSween <mike.macsween.nospam_at_btinternet.com>
Date: Sun, 5 Sep 2004 12:06:02 +0100
Message-ID: <413af318$0$6333$5a6aecb4@news.aaisp.net.uk>

"David Portas" <REMOVE_BEFORE_REPLYING_dportas_at_acm.org> wrote in message news:EJ6dnXiHr_21e6fcRVn-vQ_at_giganews.com...

Thanks David

> Is this a SQL Server or Access or database theory question?
>
> ANSI SQL92 allows DEFERRABLE constraints, which make it possible to
> implement these circular references. Unfortunately, SQL Server doesn't
> support this type of constraint. You could add an INSERT trigger to the
> Production table to insert an Event automatically. Or just insert to both
> tables in a transaction each time.

SQL Server 2000

Even if the inserts are wrapped in a transaction presumably the constraint would still apply?

All I could think of was a transaction which lifted the constraint, did the inserts, then re-applied the constraint. But seems a bit bodgy.

What database engine(s) do implement DEFERRABLE constraints?

Cheers, Mike MacSween

>
> --
> David Portas
> SQL Server MVP
> --
>
>
Received on Sun Sep 05 2004 - 06:06:02 CDT