[rules-users] on update

[Manukyan, Sergey]

Folks,

I need a rule that will track changes to cost amount and do something
with his old value.

Like that :

rule "on updated cost write to archive old value"
	when
		cost : Cost()
		old_cost : Cost(amount != cost.amount)  // how can I
specify the OLD cost object before it was updated???
	then
		... write to archive $old_cost.amount
end


Is it possible at all?

Something like in database system triggers, when you have "on update"
and then you have OLD value and NEW values available...?

Thanks a lot!

-Sergey



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