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From: jcelko212@earthlink.net (--CELKO--)
Newsgroups: comp.databases.theory
Subject: Re: How to ensure data consistency?
Date: 9 Sep 2004 08:57:46 -0700
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Xref: dp-news.maxwell.syr.edu comp.databases.theory:25888

>> there still is the problem that the main table may contain entries
for which there are no [rows in] subtables. <<

In intermediate SQL-92, all table level constraints are TRUE for an
empty table, so you need to have full SQL-92 and use a cross table
constraint.  That would be either a CREATE ASSERTION statement or a
CHECK() that has a predicate that references the other table.