Re: Object-Role Modeling?

On Sun, 10 Jul 2005 10:47:04 GMT, Jan Hidders <jan.hidders_at_REMOVETHIS.pandora.be> wrote:

>Many people seem to like to begin with ER diagrams. I happen to think
>that there's a reason for why they caught on as they did. And if you
>supply them with a formal semantics and a constraint and query language
>(which is easy to do and has in fact already been done by several
>researchers) then it qualifies as a database schema.

Then you would reinvent ORM and almost nobody would use that :)

And you would have to complement the diagrams with textual business rules anyway, like with ORM.

>Only implementation details like choosing primary keys or choosing
>whether or not to embed a one-to-many relatinship have to be skipped.
>All logically relevant details will still be in there.

What about something like: the current stock *IS* the initial stock plus the purchases and the customer's returns minus the sales, the consumption, the loses and the returns to the providers.

This is a trivial and oversimplified business rule. Business rules are a lot more complex in the real world.

Regards Received on Mon Jul 11 2005 - 12:46:29 CEST