unique primary key shared between multiple tables.
From: ben <benc_at_email.arizona.edu>
Date: 13 Mar 2003 21:31:16 -0800
Message-ID: <71915a6e.0303132131.6480504c_at_posting.google.com>
In one of my database design textbooks, I ran across the following line:
Date: 13 Mar 2003 21:31:16 -0800
Message-ID: <71915a6e.0303132131.6480504c_at_posting.google.com>
In one of my database design textbooks, I ran across the following line:
PropertyForRent(propertyNo, ownerNo)
Foreign Key ownerNo references PrivateOwner(ownerNo) and BusinessOwner(ownerNo)
This implies that I can make PrivateOwner.ownerNo and BusinessOwner.ownerNo unique not just for thier respective tables, I can make ownerNo unique across both tables. In other words, no PrivateOwner.ownerNo may have the the same value as any BusinessOwner.ownerNo.
This would be extremely usefull, but I can't find any way to actually implement a shared primary key between tables. How do I do this?
Thanks,
Ben Received on Fri Mar 14 2003 - 06:31:16 CET