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"Billy Verreynne" <vslabs_at_onwe.co.za> wrote in message news:<9t2b0l$5ja$1_at_ctb-nnrp2.saix.net>...
> So the requirement is parent child integrity - a very valid reason (critical
> IMO). However, that can be done without necassarily having to use foreign key
> constraints, though fk constraints are the "best solution" from a pure
> database perspective.
I will add some comments to "my part" of message.
You're true, that FK are not the only solution to integrity issues.
You can also enforce consistency in application code. However I have
very bad experiences with this approach. If you will write code
yourself, you can make everything OK, but data warehouses are usually
a team project, sometimes even a big team project. Maybe three or more
programmers will work on your warehouse, so all depends how these
programmers will be good and have a proper discipline. The second
requirement is very seldomly fulfilled. If only one of them forgot in
some part of code to implement these "SW constraints" or implement
them badly, then you will run into big problems.
My opinion is that FK constraints are the best solution, becuase
they're almost dumbproof.
If you don't want to use them, then you have one more way. You can
write your checking scripts to test integrity. I had complex scripts,
while clearing shit out of that data warehouse mentioned in my
previous post. You must take into account that these scripts sometimes
runs for several hours, but data warehouses are only seldomly 24x7
system (typically DWs in multinational corporations), so usually you
have a time enough to run them.
-- _________________________________________ Dusan Bolek, Ing. Oracle team leader Note: pagesflames_at_usa.net has been cancelled due to changes (maybe we can call it an overture to bankruptcy) on that server. I'm still using this email to prevent SPAM. Maybe one day I will change it and have a proper mail even for news, but right now I can be reached by this email.Received on Fri Nov 16 2001 - 09:06:42 CST