Transform_Null_Equals does not work in Functions
Hy Group,
we use:
PostgreSQL 9.0alpha4, compiled by Visual C++ build 1400, 32-bit
and i tried to set Transform_null_equals in a Trigger to avoid a complex
If Statement with many Coalesce, but it didnt work. You can try it
easily with that example:
CREATE OR REPLACE FUNCTION show_transform_problem(with_transform BOOL)
RETURNS BOOL AS $$
DECLARE result BOOL;
BEGIN
IF with_transform THEN
SET transform_null_equals TO ON;
END IF;
RESULT:=NULL=1;
SET transform_null_equals TO OFF;
RETURN result;
END $$ LANGUAGE plpgsql;
SUNFLOWER=# SELECT show_transform_problem(false);
show_transform_problem
------------------------
(1 row)
SUNFLOWER=# SELECT show_transform_problem(true);
show_transform_problem
------------------------
(1 row)
SUNFLOWER=# SET transform_null_equals TO ON;
SET
SUNFLOWER=# SELECT null=1;
?column?
----------
f
(1 row)
--
Daniel Schuchardt
/Softwareentwicklung/
Daniel Schuchardt <d.schuchardt@prodat-sql.de> writes:
CREATE OR REPLACE FUNCTION show_transform_problem(with_transform BOOL)
RETURNS BOOL AS $$
DECLARE result BOOL;
BEGIN
IF with_transform THEN
SET transform_null_equals TO ON;
END IF;
RESULT:=NULL=1;
SET transform_null_equals TO OFF;
RETURN result;
END $$ LANGUAGE plpgsql;
That isn't going to work unless you EXECUTE the target statement, so
that it's re-parsed from scratch every time.
It's highly unlikely that transform_null_equals will solve your problem
anyway. Find a more standards-compliant way.
regards, tom lane