Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!mtxinu!sybase!southbay!negris
From: negris@southbay.sybase.com (Tim Negris)
Newsgroups: comp.databases
Subject: Re: Referential Integrity in commercial DBMS's?
Message-ID: <6000@sybase.sybase.com>
Date: 12 Sep 89 14:07:16 GMT
References: <5030@merlin.usc.edu>
Sender: news@sybase.sybase.com
Reply-To: negris@southbay.UUCP (Tim Negris)
Organization: Sybase, Inc.
Lines: 16

SQL Server from Sybase will do what you want.
It's available on OS/2 platforms and it provides for complete database integrity.
Sybase allows you to define Primary and Foreign Key and create Triggers for data modification operations.
Triggers are stored procedures which are automatically executed by the database when some predefined event occurs.
When you attempt to UPDATE, INSERT, or DELETE the database will automatically execute the appropriate trigger.

In addition to referential integrity Sybase also provides for other kinds of database integrity:

Entity Integrity (of course) - Primary keys must contain unique, non-null values.
Domain Integrity - A column value must be of a given type, belong to a given set of values, and have a given format.

User-defined Integrity - Sybase allows you to write explicit rules that must be obeyed by the data and programs.  
In conjunction with triggers and other stored procedures, plus user-defined data types, you can make accommodate arbitrary events and state changes not accounted for with referential integrity.

Very few other databases that I'm aware of provide this level of integrity.