From: Martijn Tonies
Date: May 27 2004 2:55pm
Subject: Re: Foreign Key Constraints
List-Archive: http://lists.mysql.com/mysql/166259
Message-Id: <049401c443fa$af02fc70$0a02a8c0@martijn>
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Hi,

> > Why not? What's wrong with this:
> >
> > BORROWER
> > BorrowerID
> >
> > BOOKS
> > BookID
> > BorrowerID (nullable)
> >
> > FK from Books.BorrowerID to Borrower.BorrowerID
> >
> > I haven't checked, but this _should_ be possible.
> >
> > With regards,
>
> Its a foreign key, you can not null foreign keys.. Thats the problem.

If this really is the case with MySQL, then this is the only database
engine that I know that doesn't allow this.

With regards,

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