Erik Jones wrote:
On Mar 24, 2008, at 2:18 PM, Josh Trutwin wrote:
On Mon, 24 Mar 2008 14:02:02 -0500
Erik Jones <erik@xxxxxxxxxx> wrote:
On Mar 24, 2008, at 1:09 PM, Martijn van Oosterhout wrote:
On Mon, Mar 24, 2008 at 12:47:43PM -0500, Josh Trutwin wrote:
My code to check if an aggregate exists runs this query:
SELECT * FROM pg_catalog.pg_aggretate WHERE aggfnoid =
'foo'::REGPROC;
Seems to me you'd rather want the proisagg column in pg_proc and
forget
about pg_aggregate altogether...
Also, the idiom for checking if something is present is normally:
SELECT 1 FROM some_table WHERE ...;
This way you aren't dealing with errors, if it doesn't exist the
query simply doesn't return any results.
This one still does return an error though I think because of the
cast:
select 1 from pg_catalog.pg_aggregate where aggfnoid =
'foo'::regproc;
ERROR: function "foo" does not exist
As Martijn pointed out, use pg_proc instead of pg_aggregate:
SELECT 1 from pg_proc WHERE proname='foo' AND proisagg IS TRUE;
And, as Alvarro pointed out in another reply, you'll probably want to
include conditions in your where clause for the argument types.
Now I'd go the other way and SELECT count(*) FROM....
If it ain't there you get 0 returned - no errors.
In your function you can test >0 and return true else false or you can
return the count and test numerically against the return.
--
Shane Ambler
pgSQL (at) Sheeky (dot) Biz
Get Sheeky @ http://Sheeky.Biz
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