Quasi Foreign Key
From: Steve Long <steven.long_at_erols.com>
Date: Tue, 31 Oct 2000 11:13:07 -0500
Message-ID: <8tmqrt$bl0$1_at_bob.news.rcn.net>
Date: Tue, 31 Oct 2000 11:13:07 -0500
Message-ID: <8tmqrt$bl0$1_at_bob.news.rcn.net>
i have the following scenario and could use some assistance.
parent table has composite primary key consisting of three columns.
child table has a column which has a foreign key to parent table using the
first column of the parent table's composite primary key. however, the
child table's column may be null, but if it is not null it's value must be
present in the parent table's column.
the problem is that the value "null" in the child table's column is not an
allowable value in the parent table's column since in the parent table this
column is part of the primary key.
any suggestions on how to implement this?
Received on Tue Oct 31 2000 - 17:13:07 CET