Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!rpi!brutus.cs.uiuc.edu!apple!mrspoc!itkin
From: itkin@mrspoc.Transact.COM (Steven M. List)
Newsgroups: comp.databases
Subject: Re: Unique code numbers
Message-ID: <1990Jan16.211727.20403@mrspoc.Transact.COM>
Date: 16 Jan 90 21:17:27 GMT
References: <1990Jan16.081519.279@cs.eur.nl>
Reply-To: itkin@guinan.Transact.COM
Organization: Transact Software, Inc., Los Altos, CA
Lines: 40

reino@cs.eur.nl (Reino de Boer) writes:

>I was wondering if there is a relational DBMS that gives me the
>opportunity to indicate that:
>1. SupplierIDs need to be unique
>2. PartIDs need to be unique
>and, most important of all
>3. Frees me from the burden to make up new SupplierIDs and PartIDs.

>The problem is solvable by introducing a new relation for each ID:
>IDconfig = (lastID)
>and generating the new unique ID by something along
>ID <- retrieve( lastID )
>update( lastID )
>store( lastID )

>but I would like a more general mechanism. Perhaps a special field data
>type `unique id', that generates a new value when needed.

Unify (both 4.0 and the newer Unify 2000) permit you to specify that
a field should take on a unique value.  The number is automatically
assigned by the system, so it frees you from having to take care of
it.  The only drawback to Unify's system is that the number is only
unique as long as the record exists in the database, since they use the
Row ID for the unique value, and Unify's Row IDs are guaranteed to be
unique and to remain attached to the record as long as the record is
in the database.
--
 +----------------------------------------------------------------------------+
 :                Steven List @ Transact Software, Inc. :^>~                  :
 :           Chairman, Unify User Group of Northern California                :
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-- 
 +----------------------------------------------------------------------------+
 :                Steven List @ Transact Software, Inc. :^>~                  :
 :           Chairman, Unify User Group of Northern California                :
 :     {apple,coherent,limbo,mips,pyramid,ubvax}!itkin@guinan.Transact.COM    :