Re: Install new perl test function in PostgreSQL - Mailing list pgsql-novice

From Jignesh Shah
Subject Re: Install new perl test function in PostgreSQL
Date
Msg-id c11950270908260742n1c6e7388t6c28f2adae242751@mail.gmail.com
Whole thread Raw
In response to Re: Install new perl test function in PostgreSQL  (Jignesh Shah <jignesh.shah1980@gmail.com>)
Responses Re: Install new perl test function in PostgreSQL
List pgsql-novice
Michael, I have one question. I have written a perl code for detecting trigger type(insert, update or delete) and based on that performing the operation. Now I want to make this code as a trigger. Coud you tell me I have to copy paste all written lines while creating function for it or I can create file somewhere and give it as a input?  Please let me know if below are correct way to do it?

CREATE FUNCTION my_perlfunc (integer, integer) RETURNS VOID
  AS       *** Large number of lines Perl code ***
LANGUAGE plperl;

CREATE TRIGGER my_trigger AFTER INSERT OR UPDATE OR DELETE ON my_table
    FOR EACH ROW EXECUTE PROCEDURE my_perlfunc(integer, integer);
Moreover, I have tried to create trigger like below to execute perl_max function but it gives error. Am I missing something?
 
mydb=# SELECT perl_max(13,9);
       13
 
mydb=# CREATE TRIGGER my_trigger AFTER INSERT OR UPDATE OR DELETE ON my_table
mydb-#     FOR EACH ROW EXECUTE PROCEDURE perl_max(integer, integer);
ERROR:  function perl_max() does not exist
Thanks for being there.
 
Jignesh
On Wed, Aug 26, 2009 at 4:07 PM, Jignesh Shah <jignesh.shah1980@gmail.com> wrote:
That was a perfect answer Michael. It worked. Thanks.


On Wed, Aug 26, 2009 at 12:31 PM, Michael Wood <esiotrot@gmail.com> wrote:
2009/8/26 Jignesh Shah <jignesh.shah1980@gmail.com>:
> Thanks Jure. I have already plperl installed because I could see that many
> new perl functions have been installed but I don't know where it plperl
> installed. Could you tell me if there is any way to find out where it is
> installed? Morever, if I get the location plperl install location, how to
> insert/install my perl function? Is there any command available for this. My
> questions might be silly but this is first time I am using PostgreSQL.

If it PL/Perl is installed in your database then you do not need to
know "where it is".  It's in your database.  So you can just create
your function and it should work.  e.g.:

$ psql dbname
Welcome to psql 8.3.1, the PostgreSQL interactive terminal.

Type:  \copyright for distribution terms
      \h for help with SQL commands
      \? for help with psql commands
      \g or terminate with semicolon to execute query
      \q to quit

dbname=> SELECT * FROM pg_language;
 lanname  | lanowner | lanispl | lanpltrusted | lanplcallfoid |
lanvalidator | lanacl
----------+----------+---------+--------------+---------------+--------------+--------
 internal |       10 | f       | f            |             0 |         2246 |
 c        |       10 | f       | f            |             0 |         2247 |
 sql      |       10 | f       | t            |             0 |         2248 |
(3 rows)

dbname=> CREATE LANGUAGE plperl;
CREATE LANGUAGE
dbname=> SELECT * FROM pg_language;
 lanname  | lanowner | lanispl | lanpltrusted | lanplcallfoid |
lanvalidator | lanacl
----------+----------+---------+--------------+---------------+--------------+--------
 internal |       10 | f       | f            |             0 |         2246 |
 c        |       10 | f       | f            |             0 |         2247 |
 sql      |       10 | f       | t            |             0 |         2248 |
 plperl   |    16386 | t       | t            |         19193 |        19194 |
(4 rows)

dbname=> CREATE FUNCTION perl_max (integer, integer) RETURNS integer AS $$
dbname$>     if ($_[0] > $_[1]) { return $_[0]; }
dbname$>     return $_[1];
dbname$> $$ LANGUAGE plperl;
CREATE FUNCTION
dbname=> SELECT perl_max(55, 23);
 perl_max
----------
      55
(1 row)

dbname=> SELECT perl_max(55, 97);
 perl_max
----------
      97
(1 row)

dbname=>

See also:
http://www.postgresql.org/docs/8.4/static/xplang.html
http://www.postgresql.org/docs/8.4/static/plperl.html

--
Michael Wood <esiotrot@gmail.com>


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