Re: How to know a record has been updated, then reset the flag?

Jim,

How about having the trigger write the pk of the table to a new table. The
backend processing could then just join the new table on the pk to the
existing table to give you a proper result set. In the same transaction
delete the contents of the new pk table. Not as efficient as setting a
flag but relationally sound and portable.

Note that this problem cries out for column triggers. I don't know if
anyone has them on a to do list.

Rick

Jim Archer
<jim(at)archer(dot)net> To: pgsql-general(at)postgresql(dot)org
Sent by: cc:
pgsql-general-owner(at)pos Subject: [GENERAL] How to know a record has been updated, then reset the flag?
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11/18/2004 12:53 AM
Please respond to Jim
Archer

Hi All...

I'm been fighting this problem for a few days now, and it seems like it
should be simple. But the solution has eluded me so far...

I need to flag a record when it is updated or when it is a new insert.
Then I SELECT for the changed records and do something not related to
Postgres. Easy enough, I created a trigger procedure and fired it on
INSERT OR UPDATE and modify NEW to set the flag field to true.

But then the problem is how do I reset the trigger? If I do an UPDATE the
trigger fires again. I thought I could check for the flag field being NULL

and that works for an INSERT, but apparently if it is an update NEW
contains the existing value of the field.

I am trying to avoid modifying the cost the needs to set the flags (I can
change the schema), but I have full control over the code that has to reset

them. Is there a way I can update a record without firing the trigger, or
by bypassing it? This is a multi-user environment, so I can't really drop
the trigger and readd it.

Is there a solution not related to this?

I would appreciate some help, thanks very much!

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