Re: PL/pgSQL 2

On 09/01/2014 05:04 PM, Joel Jacobson wrote:
> From the top of my head, these are Things I personally would want to see
> in plpgsql2:

Oh, also, I'd *love* to improve how non-plannable statements with
PL/PgSQL variable subsitutions behave.

*I* understand why the following is wrong:

DO
$$
DECLARE
tablename text;
BEGIN
tablename := 'sometable';
DROP TABLE tablename;
END;
$$;

and produces:

ERROR: table "tablename" does not exist
CONTEXT: SQL statement "DROP TABLE tablename"
PL/pgSQL function inline_code_block line 6 at SQL statement

but going by the number of questions I see about this, and similar
issues with ALTER USER and so on, it's not obvious to new users.

It's not clear how to make this friendly without making it dangerous
though. If you have:

DROP TABLE x;

then someone declares a variable

x := 'customers';

you don't want to suddenly be issuing a

DROP TABLE customers;

... which is why I suspect this might need to be not 100% backward
compatible, perhaps requiring a variable-marker prefix.

--
Craig Ringer http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services