Re: psql - add special variable to reflect the last query status

Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr> writes:
> Small v7 update, sorry for the noise.

Hm. Looking closer at this, I see that it doesn't work so well after all
to put the variable-setting code in ProcessResult: that fails to cover the
ExecQueryUsingCursor code path. And it also fails to cover DescribeQuery,
which arguably should set these variables as well -- certainly so if it
gets a failure. Maybe you could create a small subroutine along the lines
of SetResultVariables(PGresult *result, bool success) for all three places
to call. (ProcessResult certainly has already decided whether it's got a
success, and I think the other paths would know that as well, so no need
to re-extract it from the PGresult.)

I think you're overly optimistic to believe that every failure will
have a SQLSTATE; I don't think that's true for libpq-reported errors,
such as connection loss.

Using upper-case TRUE/FALSE for the values of ERROR seems a bit
ugly to me; we generally use lower case for other variable values,
so I'd go with true/false.

regards, tom lane