Re: How to use dblink within pl/pgsql function:

Clive Page wrote:
> What I'd like to do is use dblink to extract a few rows from a remote
> database and manipulate these within a function in pl/pgsql.  Something
> like this:
>
> CREATE OR REPLACE FUNCTION find() RETURNS INTEGER AS '
>   DECLARE
>     count INTEGER:
>     myrec RECORD;
>   BEGIN
>   FOR myrec IN SELECT * FROM DBLINK(''select x,y from mytab'') as
>      temp(x integer, y real) LOOP
>      count := count + 1;
>   END LOOP;
>   RETURN count;
> END; ' LANGUAGE 'plpgsql';
>
>
> But this syntax does not work, and I cannot find a form which does work.
> Does anyone know how to do this?

You didn't show us the specific error you get, making it difficult to help.

Offhand I see two errors in your script above unrelated to the use of
dblink, and possibly one related to dblink. First, the line "count
INTEGER:" ends in a colon instead of the required semicolon. Second, if
you don't initialize "count" to something other than NULL, adding 1 to
it will still add null. Try this:

CREATE OR REPLACE FUNCTION find() RETURNS INTEGER AS '
   DECLARE
     count INTEGER := 0;
     myrec RECORD;
   BEGIN
   FOR myrec IN SELECT * FROM DBLINK(''select x,y from mytab'') as
      temp(x integer, y real) LOOP
      count := count + 1;
   END LOOP;
   RETURN count;
END; ' LANGUAGE 'plpgsql';

The dblink issue is that you've used a form of dblink that requires you
to have previously set up a connection. If you call your find() function
without first establishing that connection, you'll get a "ERROR:
connection not available" or something similar. See the dblink docs.

Joe