Re: foundations of relational theory?

Tony Gravagno <g6q3x9lu53001_at_sneakemail.com.invalid> wrote in message news:<ndjrpvgdq9n3f3t0tpi3hcddom1910aohm_at_4ax.com>...
> Comment, not correction: Since the concept of triggers is mentioned,
> sure, other MV flavors have triggers as well. Data updates invoke
> programs, which, as part of the application, serve to update other
> data, perhaps invoking other triggers in the process. The presence of
> triggers doesn't guarantee database integrity, triggers are just
> another tool to centralize application-driven integrity constraints on
> the database.
>
> Now to Bob's comment: "the whole point of a logical data model is to
> keep logical integrity issues from becoming implementation specific" -
> gimme a break... Every relational environment has a different
> implementation of SQL, different internal file structures, and
> different mechanisms for managing updates with record locks.

SQL is not a very good logical data model due both to fundamental flaws in the model and due to vendor pollution of the language with different logical features. You won't hear me state otherwise. More to the point, SQL provides almost no support for integrity. Regardless, the whole point of a logical data model is to keep logical integrity issues from becoming implementation specific.

Internal file structures and other internal mechanisms have nothing to do with a logical data model. Internal issues are, as the name implies, properly implementation specific.

Your ignorance and stupidity underwhelm me. Sadly, my ISP still has not corrected the problems with the news server. Received on Wed Oct 29 2003 - 15:26:44 CET