Adam Hardy (11/11/2008)
Guys, your making me suck eggs here,Yes data integrity tasks on the most part can be modelled with PKs and FKs. Those that can't, can be modelled with triggers. I've used triggers on tables containing critical data where I wanted to protect the data even when a modification has come from a source I hadn't expected (e.g. Some idiot running a query they shouldn't).
Now I suppose you'll tell me to use stored procedures and user permissions to achieve the same goal. I could, but wont as at this stage the triggers would be easier to implement and I honestly don't care about the performance hit in this particular area of the system (it will be negligible at best). There are no nested triggers.
Yes "data integrity" is the lowest form of "business rule". I didn't actually use that term either, I said "business related stored procs" (a business related function implemented in the data tier for performance). Hopefully now we can dispense with the semantics as they are not really relevant to the question I asked.
Adam.
Actually - the cost isn't so bad if you use a BEFORE trigger (the update hasn't happened yet, so there wouldn't be two separate updates.). Of course - you only get just one of these per table.
Of course - now the scenario flips and you have to be sure to issue the ones you want to commit to the table, or your INSTEAD OF trigger acts as a barrier to entry....
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Your lack of planning does not constitute an emergency on my part...unless you're my manager...or a director and above...or a really loud-spoken end-user..All right - what was my emergency again?