Re: How to check if a field exists in NEW in trigger

po 5. 8. 2019 v 7:55 odesílatel Thomas Kellerer <spam_eater(at)gmx(dot)net> napsal:

> Igal @ Lucee.org schrieb am 05.08.2019 um 00:52:
> > I have the following statement in a trigger:
> >
> > new.email = lower(new.email);
> >
> > When I try to update a record without setting the email column however,
> I get an error:
> >
> > SQL Error [42703]: ERROR: record "new" has no field "email"
> > Where: SQL statement "SELECT lower(new.email)"
> > PL/pgSQL function on_record_modified() line 26 at assignment
> >
> > I have seen some hacks suggesting TRY/CATCH or converting to a JSON
> > and checking if the field exists, but I would think that there's a
> > better way to check if the field is in the NEW record, no?
>
>
> I assume using to_jsonb(new) and then check for the key in the json value
> will be faster than checking e.g. information_schema.column
> or pg_catalog.pg_attribute
>

Alternative solution can be using other language than PLpgSQL - PLPythonu
or PLPerl (there it is simple task). This language is not designed for too
dynamic code. PLpgSQL triggers are designed for stable schema - you should
to know if table has email column or not.

Catching errors in PLpgSQL is relative expensive solution due related
savepoint overhead in background.

Regards

Pavel