I was confronted with a similar problem. I have several scripts which create
or modify schemas, and each run in a single transaction. So, dropping a
non-existent TYPE will produce a show-stopping error. I wrote this function,
and others for various database objects:
CREATE OR REPLACE FUNCTION dba_droptype(varchar) RETURNS boolean AS '
DECLARE p_type ALIAS FOR $1; v_exists boolean;
BEGIN SELECT INTO v_exists TRUE WHERE EXISTS( SELECT 1 FROM pg_type WHERE typname = p_type::name); IF
v_existsTHEN RAISE NOTICE ''Dropping TYPE %'', p_type; EXECUTE ''DROP TYPE '' || p_type || '' CASCADE''; END
IF; RETURN FOUND;
END;
' LANGUAGE 'plpgsql';
COMMENT ON FUNCTION dba_droptype(varchar) IS '
Usage: SELECT dba_drop_type(type_name)
Checks for existence of a type and drops it if found.
Implements DROP TYPE CASCADE; if a function or other object
depends on the type, that object will also be dropped.
Returns TRUE if successful, returns FALSE if type is
not found.';
--
Craig Addleman
DBA
ShareChive LLC
* Philippe Lang <philippe.lang@attiksystem.ch> [2005-04-06 05:59]:
> Hi,
>
> Since it is not possible to use CREATE OR REPLACE TYPE, is there a way
> of using DROP TYPE on a non-existing type, without causing the entire
> script to abort? It may sound crazy to ask for this, but it could be
> really useful in my case, where Pl/Pgsql and Pl/Perl code is being
> generated automatically, based on data found in a database.
>
> Thanks
>
> -----------------
> Philippe Lang
>
>
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