Re: Separate PK in Jxn Tbl?
Date: Fri, 1 Feb 2008 07:33:29 -0000
Message-ID: <1IKdncuZltPXVj_anZ2dneKdnZydnZ2d_at_pipex.net>
"Brian Selzer" <brian_at_selzer-software.com> wrote in message
news:p9uoj.5279$0o7.473_at_newssvr13.news.prodigy.net...
>
I agree very heartily with the first part of this statement, for the reasons
you give below. I disagree with the second part (as stated). There is no
reason why applications shouldn't also test what constraints they can. The
problem is that they should not have hand-coded re-implementations of the
constraints because those will get out of sync with the database over time.
What would be very nice is if one day it were possible for applications to
download the relevant constraints at run-time, the way they presently
download other metda-data.
> Constraints should always be checked by the DBMS, not by applications.
> If you have two separate applications that manipulate the same table, and
Roy
> one enforces one constraint while another enforces another, then all you
> need to do to bypass one constraint is to use the other application!
> What, then, is the point of even having the constraint?