Re: database market share 2003

> > Oracle got fewer points than DB2 (and they would
> > probably get even fewer points from Codd today since Oracle seems to
have
> > moved away from relational in many respects).
> >
>
>"Mark Townsend" <markbtownsend_at_comcast.net> wrote in message
news:40D063E8.7060308_at_comcast.net...
> I've seen you make this point before
>

http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&selm=1Jqab.76%24ZR1.81776%40news.uswest.net
>
> I challenged you at the time, and can't remember if you ever came back
> with an example - so exactly what is it in Oracle that you think has
> moved away from the relational model ?
>

With Oracle (a little more than some other RDBMS's) programmers and users who access the data want to know (or need to know depending on your point of view) a little bit about the way the data is physically organized. This includes things like rowids, certain kinds of indexes, etc. In a pure relational model, the physical structure of the data is isolated from the logical structure.

This movement away from a pure relational model is done for performance reasons or to add features that some programmers may want. Nevertheless these features (no matter how much people want them) often are in violation of both Codd's rules and ANSI SQL standards.

Even if you don't take my word on this subject, it was clear that Codd originally rated Oracle as less relational than DB2 (according to his 12 rules), and Oracle has gone way beyond the SQL standards (and often the relational model) since that time. Received on Wed Jun 16 2004 - 11:09:43 CDT