Re: pgsql: Fix documentation template for CREATE TRIGGER.

On Sat, 2014-06-21 at 14:21 +0000, Kevin Grittner wrote:
> Fix documentation template for CREATE TRIGGER.
>
> By using curly braces, the template had specified that one of
> "NOT DEFERRABLE", "INITIALLY IMMEDIATE", or "INITIALLY DEFERRED"
> was required on any CREATE TRIGGER statement, which is not
> accurate.  Change to square brackets makes that optional.
>
> Backpatch to 9.1, where the error was introduced.

It still doesn't look quite right to me. The new form:

[ NOT DEFERRABLE | [ DEFERRABLE ] { INITIALLY IMMEDIATE | INITIALLY
DEFERRED } ]

says that, if DEFERRABLE is specified, then INITIALLY IMMEDIATE or
INITIALLY DEFERRED is required. But the following is accepted by the
server:

  create constraint trigger mytrigger
    after insert on dummy_table deferrable
    for each row execute procedure dummy_trigger();

(Although the standard doesn't seem to have deferrable triggers, that
does seem to match the deferrable constraint syntax that is in the
spec.)

For that matter, the following is also accepted by the server:

  create constraint trigger mytrigger
    after insert on dummy_table initially deferred deferrable
    for each row execute procedure dummy_trigger();

That case may be a bug; and regardless I don't think we want to
document/encourage specifying them in that order. But the first case
seems reasonable to me.

Regards,
    Jeff Davis