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Posted by Erland Sommarskog on 09/29/46 11:55
(dba_222@yahoo.com) writes:
> I'm an Oracle guy, who is being given more SQL Server assignments
> lately.
>
> I've been looking for things on the web about this, but I can't
> anything so far.
>
> In Oracle, I you can create a trigger on a table that -only- fires if
> certain fields are updated.
>
> create or replace trigger trg_some_trigger
> BEFORE insert
> OF some_field1, some_field2
> on tbl_some_table
> for each row
>
> ...
>
As Mike said, the best you can do is to check in the trigger whether
a columns was updated:
IF UPDATE(col)
BEGIN
-- Do stuff
END
But keep in mind that this not tell you whether any values in the
column were changed, only that it was mention in the SET clause of
an UPDATE statement. And for INSERT the condition is alwauys tru.
Also keep in mind that in SQL Server a trigger fires once per
statement, not once per row.
And, finally, there are no BEFORE triggers in SQL Server. Only INSTEAD OF
triggers and AFTER triggers.
--
Erland Sommarskog, SQL Server MVP, esquel@sommarskog.se
Books Online for SQL Server 2005 at
http://www.microsoft.com/technet/prodtechnol/sql/2005/downloads/books.mspx
Books Online for SQL Server 2000 at
http://www.microsoft.com/sql/prodinfo/previousversions/books.mspx
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