Re: Create a trigger only for certain users

On 05/11/2016 07:12 AM, Ezequiel Luis Pellettieri wrote:
> Hi guys, I'm going to build a trigger on update for a few tables, but I
> have to ignore updates for certain users. Is there a way to accomplish
> this task?

A thought, assuming plpgsql:

1) Use session_user/current_user:
http://www.postgresql.org/docs/9.5/interactive/functions-info.html

2) In BEFORE trigger code:
http://www.postgresql.org/docs/9.5/interactive/plpgsql-trigger.html

test for the user and return NULL if there is a match:

"Row-level triggers fired BEFORE can return null to signal the trigger
manager to skip the rest of the operation for this row (i.e., subsequent
triggers are not fired, and the INSERT/UPDATE/DELETE does not occur for
this row)."

Another thought, assuming Postgres 9.5+:

Use Row Level Security:

http://www.postgresql.org/docs/9.5/static/sql-createpolicy.html

>
> Thanks in advance.
>
> Regards.
> Pelle.-
>
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--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com