Re: efficient compare

From: David Cressey <dcressey_at_verizon.net>
Date: Sat, 22 Apr 2006 12:30:23 GMT
Message-ID: <zlp2g.2293$Qe.2272@trndny09>

"Andersen" <andersen_800_at_hotmail.com> wrote in message news:444A107F.8060605_at_hotmail.com...

> Right, I will periodically do this unification, to try to keep the
> replicated dbms in sync.

Is your question really about keeping two tables in sync? I intend the word "tables", rather than "sets" or "relations".

If so, I have a question? How will one ever delete data from (A union B)? Does it require a delete to A and a delete to B before the synchronizer has a chance to undo the deletion?

Also, what wrong with having a rule that enforces uniqueness in A and B, and just copying one table over to the other, while throwing away entries rejected by the duplicate catcher?

Is this a question requiring a theoretical answer or are you trying for a practical solution? Received on Sat Apr 22 2006 - 07:30:23 CDT