Обсуждение: Handy user/group hack

Kind people,

Here's something I came up with for finding whether a PostgreSQL 7.4
user is in a group.

Cheers,
D

CREATE OR REPLACE FUNCTION in_group (text, text) RETURNS BOOLEAN AS '
DECLARE   the_user  ALIAS FOR $1;   the_group ALIAS FOR $2;   dummy text; -- SELECT INTO dummy because PERFORM always
returnstrue.               -- Is this a bug?
 
BEGIN   SELECT INTO dummy u.usename   FROM     pg_user u   , pg_group g   WHERE       u.usename = the_user   AND
g.groname= the_group   AND u.usesysid = ANY (g.grolist);
 
   IF FOUND   THEN       RETURN true;   ELSE       RETURN false;   END IF;
END;
' LANGUAGE 'plpgsql' STRICT IMMUTABLE;
-- 
David Fetter david@fetter.org http://fetter.org/
phone: +1 510 893 6100    cell: +1 415 235 3778

Here's a slightly condensed version - do SQL functions have an advantage in
that they can be inlined? Or have I misunderstood?

CREATE OR REPLACE FUNCTION user_in_group(name,name) RETURNS boolean STRICT
AS 'SELECT EXISTS(SELECT u.* FROM pg_catalog.pg_user u INNER JOIN
pg_catalog.pg_group g ON (u.usesysid = ANY(g.grolist)) WHERE u.usename = $1
AND g.groname = $2);
' LANGUAGE 'SQL';


"David Fetter" <david@fetter.org> wrote in message
news:20031121040927.GJ6395@fetter.org...
> Kind people,
>
> Here's something I came up with for finding whether a PostgreSQL 7.4
> user is in a group.
>
> Cheers,
> D
>
> CREATE OR REPLACE FUNCTION in_group (text, text) RETURNS BOOLEAN AS '
> DECLARE
>     the_user  ALIAS FOR $1;
>     the_group ALIAS FOR $2;
>     dummy text; -- SELECT INTO dummy because PERFORM always returns true.
>                 -- Is this a bug?
> BEGIN
>     SELECT INTO dummy u.usename
>     FROM
>       pg_user u
>     , pg_group g
>     WHERE
>         u.usename = the_user
>     AND g.groname = the_group
>     AND u.usesysid = ANY (g.grolist);
>
>     IF FOUND
>     THEN
>         RETURN true;
>     ELSE
>         RETURN false;
>     END IF;
> END;
> ' LANGUAGE 'plpgsql' STRICT IMMUTABLE;
> -- 
> David Fetter david@fetter.org http://fetter.org/
> phone: +1 510 893 6100    cell: +1 415 235 3778
>
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