Re: Update and trigger - Mailing list pgsql-sql

From A. Kretschmer
Subject Re: Update and trigger
Date
Msg-id 20080611052107.GA24984@a-kretschmer.de
Whole thread Raw
In response to Update and trigger  ("Medi Montaseri" <montaseri@gmail.com>)
Responses Re: Update and trigger
List pgsql-sql
am  Tue, dem 10.06.2008, um 18:45:51 -0700 mailte Medi Montaseri folgendes:
> Hi,
> 
> I need to increament a counter such as myTable.Counter of type integer
> everytime myTable.status a boolean column is updated. Can you help me complete
> this...
> 
> create trigger counter_trigger after update on myTable.counter
> execute procedure 'BEGIN statement; statement; statement END'

much simpler, use a RULE instead a TRIGGER like my example:

Suppose, i have a table called foo, it contains now:

test=# select * from foo;i
---12
(2 rows)


I create a sequence and a RULE:

test=*# create sequence foo_counter;
CREATE SEQUENCE
test=*# create or replace rule foo_update as on update to foo do also select nextval('foo_counter');
CREATE RULE


And now i do a update on foo:


test=*# update foo set i=2;nextval
---------      1
(1 row)

test=*# update foo set i=3;nextval
---------      2
(1 row)


test=*# select currval('foo_counter');currval
---------      2
(1 row)



Andreas
-- 
Andreas Kretschmer
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