TG_COLUMNS_UPDATED

 

I would like another TG_* special variable to be available to a PL/pgSQL trigger-function.

 

     TG_COLUMNS_UPDATED 

 

Its value would be NULL unless: TG_OP == ' UPDATE' and TG_LEVEL == 'ROW'

 

Data type == varbit

One bit for each column of the table that the trigger is created on.

     1 means that the column was in the set clause of the update statement that made the trigger fire

     0 means it was not

 

I understand that CREATE TRIGGER already has

     UPDATE [ OF column_name [, ... ] ]

 

 

Is this a relatively straightforward enhancement ?

 

It would allow me to know whether various timestamp columns in the row were

unlucky enough to have been set to the same exact value already existing in the table

*versus* were simply not set by the UPDATE statement.

 

Thanks,

-dvs-