Can a nested function determine it is being called within a trigger?
When a trigger calls a function, that function can determine if it is being called from within a trigger by testing for a value in the special variable "TG_OP".
But what if a trigger calls a function that calls a 2nd function via the "PERFORM" command? Can that 2nd function tell if it is being run in a trigger?
Trigger --> Function_A --> Function_B
--Basil Bourque
Basil Bourque <basil.list@me.com> writes:
When a trigger calls a function, that function can determine if it is being called from within a trigger by testing for a value in the special variable "TG_OP".
Uh, no, not really. TG_OP is a local variable in the trigger function;
it's not visible from elsewhere.
But what if a trigger calls a function that calls a 2nd function via the "PERFORM" command? Can that 2nd function tell if it is being run in a trigger?
No. Doesn't really matter whether you use PERFORM or not.
regards, tom lane
On 04/15/2011 05:36 PM, Tom Lane wrote:
Basil Bourque<basil.list@me.com> writes:
When a trigger calls a function, that function can determine if it is being called from within a trigger by testing for a value in the special variable "TG_OP".
Uh, no, not really. TG_OP is a local variable in the trigger function;
it's not visible from elsewhere.But what if a trigger calls a function that calls a 2nd function via the "PERFORM" command? Can that 2nd function tell if it is being run in a trigger?
No. Doesn't really matter whether you use PERFORM or not.
regards, tom lane
One could pass a boolean from function A to B, I suppose.