Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!db.toronto.edu!mendel
From: mendel@db.toronto.edu (Alberto Mendelzon)
Newsgroups: comp.databases
Subject: Re: OODMS-RDBMS Wars (Was: Extended RDB vs OODB)
Keywords: CASE OODB
Message-ID: <1989Aug24.114401.27591@jarvis.csri.toronto.edu>
Date: 24 Aug 89 15:44:02 GMT
References: <3560052@wdl1.UUCP> <408@odi.ODI.COM> <3324@rtech.rtech.com> <1037@unify.UUCP> <161@servio.UUCP>
Organization: University of Toronto, CSRI
Lines: 26

In article <161@servio.UUCP> penneyj@servio.UUCP (D. Jason Penney) writes:
>I would like to point out my
>own personal opinion as to why an OODMS may eventually out-perform an
>x-RDBMS:  Relational systems rely on "normalizing" data into separate
>relations, and then joining the relations at query time to formulate
>results.  OODMSs essentially pre-calculate the joins.  Applications that
>are heavier on writing than reading will probably always perform better
>on an x-RDBMS, because the join calculation is deferred.  Applications
>that read the database more than they write it will win with an OODMS,
>because the need for joins during the query is eliminated.

An interesting argument, but I'm not sure it holds
water. The better a relational system is at computing
joins, the more likely that there will be a substantial
overhead at write time in updating indices, etc.
In the other direction, applications that mostly read can have their
joins pre-calculated even in a relational environment
by using constructs such as snapshots or materialized views.
In fact, the applications that
are usually mentioned as best suited to OO systems (CAx and
such) do not seem to require much more reading than
writing - or do they?

Alberto Mendelzon
University of Toronto
mendel@db.toronto.edu