Re: Normalization questions...
From: David Cressey <david_at_dcressey.com>
Date: Sun, 21 Jan 2001 23:42:17 GMT
Message-ID: <ttKa6.34752$2X4.73762_at_petpeeve.ziplink.net>
Date: Sun, 21 Jan 2001 23:42:17 GMT
Message-ID: <ttKa6.34752$2X4.73762_at_petpeeve.ziplink.net>
Pavel,
Sometimes you "discover" keys, rather than "inventing" them.
In your case, the combination uid, gid can only occur once the junction table. A uid might appear in several rows. A gid might appear in several rows. But, in combination, they are unique.
You can treat (uid, gid) as the primary key. Most DBMSes will let you declare a compound primary key.
--
Regards,
David Cressey
www.dcressey.com
Received on Mon Jan 22 2001 - 00:42:17 CET