Re: trigger, how to determine action calling?

Marcin Mazurek wrote:
>
> Hi,
> Is it possible to determine easily which action called triger?
> For example:
> CREATE TRIGGER log_znw BEFORE INSERT OR UPDATE ON tab
> FOR EACH ROW EXECUTE PROCEDURE log_tab();
> How to check in called function if it was INSERT or UPDATE?

Sure. Here's a snippet of C that does this. You might like to check
out the sample SPI programs included with the PostgreSQL source (in
/contrib/spi.)

if (!CurrentTriggerData)
elog(ERROR, "nodeinsert: triggers are not initialized");
if (TRIGGER_FIRED_FOR_STATEMENT(CurrentTriggerData->tg_event))
elog(ERROR, "nodeinsert: can't process STATEMENT events");
if (TRIGGER_FIRED_AFTER(CurrentTriggerData->tg_event))
elog(ERROR, "nodeinsert: must be fired before event");

if (TRIGGER_FIRED_BY_INSERT(CurrentTriggerData->tg_event))
trigger_tuple = CurrentTriggerData->tg_trigtuple;
else if (TRIGGER_FIRED_BY_UPDATE(CurrentTriggerData->tg_event))
/* trigger_tuple = CurrentTriggerData->tg_newtuple; */
elog(ERROR, "nodeinsert: must be fired on INSERT, not UPDATE");
else
elog(ERROR, "nodeinsert: must be fired on INSERT, not DELETE");

--

Ron Peterson
Systems Manager
Wallace Floyd Design Group
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rpeterson(at)wallacefloyd(dot)com