Re: Is it possible to get username information while writingtrigger?

a wrote:
> Please allow me to ask few more questions:
>
> 1, Since I'm writing a C trigger function, is there any method for me to get some of the
> basic information like the follow:
>
> (1) Total number of rows;
> (2) Rows' names;
> (3) Value of OLD and NEW;
>
> 2, Is there any possibility of passing the SQL statement it self into the trigger?
>
> 3, Is it possible for me to exam before statement trigger so that I would be able to loop it
> once and copying the update information to the rest of rows.

I don't know if there is a reliable way to get the SQL statement from
a C trigger.

For the other things, perhaps a statement level trigger with transition
relations can help.

You can then access the transition relations from your C code with
the tg_oldtable and tg_newtable tuplestores.
(https://www.postgresql.org/docs/current/static/trigger-interface.html)

Yours,
Laurenz Albe
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