Re: OT Re: Relational vs network vs hierarchic databases
Date: Sun, 21 Nov 2004 08:55:23 -0500
Message-ID: <TeudneHEFdDWAz3cRVn-pA_at_comcast.com>
"Marshall Spight" <mspight_at_dnai.com> wrote in message news:XkUnd.58923$V41.58239_at_attbi_s52...
> I recall a conversation with a PM (no less) in which I had proposed
> some dumb idea of how to model something with tables. The PM
> said, you'd more typically do some things like this. And he showed
> me a many-to-many table, and how you could use it and query it,
> etc. And suddenly these seemingly-simple relational operators
> were doing something quite clever, and it was actually doing
> something that was problematic in OO.
I think that this reveals something. It's the join operator that makes the
system of relations so powerful.
The restrict (select) operator is a pretty natural revision of "record
selection criteria", and the project is not easily appreciated at first.
But it's the operators that make relations useful as a type.
Received on Sun Nov 21 2004 - 14:55:23 CET