Re: Inheritance mapping in a RDBMS
From: Jonathan Leffler <jleffler_at_earthlink.net>
Date: Tue, 20 Jan 2004 06:45:38 GMT
Message-ID: <m84Pb.18649$1e.6804_at_newsread2.news.pas.earthlink.net>
>>"Maarten van der Peet" <Maarten.van.der.Peet_at_liposuctie4all.nl.invalid>
>> wrote:
>>>What I am trying to do is, map an inheritance hierarchy in a relational
>>>database system.
>>
>>None of the RDBMSs support inheritance directly, except Postgres.
>>
>>Hmmm. What about having a polymorphic set theory for databases?
>>Each set has a rowtype; each row is either of that type or a subtype.
>>This would allow polymorphic set-at-a-time operations. That would
>>be cool.
Date: Tue, 20 Jan 2004 06:45:38 GMT
Message-ID: <m84Pb.18649$1e.6804_at_newsread2.news.pas.earthlink.net>
Tom Hester wrote:
> Oracle9i supports 'type' inheritance. That is one abstract data type can > inherit from another.
IBM Informix Dynamic Server 9.x supports a form of inheritance too - with tables inheriting attributes from other 'supertype' tables.
Not very TTM, but there...
> "Marshall Spight" <mspight_at_dnai.com> wrote:
>>"Maarten van der Peet" <Maarten.van.der.Peet_at_liposuctie4all.nl.invalid>
>> wrote:
>>>What I am trying to do is, map an inheritance hierarchy in a relational
>>>database system.
>>
>>None of the RDBMSs support inheritance directly, except Postgres.
>>
>>Hmmm. What about having a polymorphic set theory for databases?
>>Each set has a rowtype; each row is either of that type or a subtype.
>>This would allow polymorphic set-at-a-time operations. That would
>>be cool.
-- Jonathan Leffler #include <disclaimer.h> Email: jleffler_at_earthlink.net, jleffler_at_us.ibm.com Guardian of DBD::Informix v2003.04 -- http://dbi.perl.org/Received on Tue Jan 20 2004 - 07:45:38 CET