Thread: Update and trigger
Hi,<br /><br />I need to increament a counter such as myTable.Counter of type integer everytime myTable.status a booleancolumn is updated. Can you help me complete this...<br /><br />create trigger counter_trigger after update on myTable.counter<br /> execute procedure 'BEGIN statement; statement; statement END'<br /><br />Q1- how do I narrow the eventto "update on a column not a row"<br />Q2- can I just provide an inline procedure for the execute<br /><br />Thanks<br/> Medi<br />
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
Kontakt: Heynitz: 035242/47150, D1: 0160/7141639 (mehr: -> Header)
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Medi Montaseri wrote: > 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' > > Q1- how do I narrow the event to "update on a column not a row" Use a row-level trigger and test to see if the column of interest has been altered. Eg: IF new.fieldname IS DISTINCT FROM old.fieldname THEN -- Do the work END IF; > Q2- can I just provide an inline procedure for the execute No, at present you must create a function that returns TRIGGER and then use that as the target to execute. At least as far as I know. -- Craig Ringer
Thanks...but a difference seems to be that the rule is not specific to update on a particular col but any col of a row
gettingupdated...<br /><br />Thanks<br /><br /><div class="gmail_quote">On Tue, Jun 10, 2008 at 10:21 PM, A. Kretschmer
<<ahref="mailto:andreas.kretschmer@schollglas.com">andreas.kretschmer@schollglas.com</a>> wrote:<br /><blockquote
class="gmail_quote"style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">am
Tue,dem 10.06.2008, um 18:45:51 -0700 mailte Medi Montaseri folgendes:<br /><div class="Ih2E3d">> Hi,<br /> ><br
/>> I need to increament a counter such as myTable.Counter of type integer<br /> > everytime myTable.status a
booleancolumn is updated. Can you help me complete<br /> > this...<br /> ><br /> > create trigger
counter_triggerafter update on myTable.counter<br /> > execute procedure 'BEGIN statement; statement; statement
END'<br/><br /></div>much simpler, use a RULE instead a TRIGGER like my example:<br /><br /> Suppose, i have a table
calledfoo, it contains now:<br /><br /> test=# select * from foo;<br /> i<br /> ---<br /> 1<br /> 2<br /> (2
rows)<br/><br /><br /> I create a sequence and a RULE:<br /><br /> test=*# create sequence foo_counter;<br /> CREATE
SEQUENCE<br/> test=*# create or replace rule foo_update as on update to foo do also select nextval('foo_counter');<br
/>CREATE RULE<br /><br /><br /> And now i do a update on foo:<br /><br /><br /> test=*# update foo set i=2;<br />
nextval<br/> ---------<br /> 1<br /> (1 row)<br /><br /> test=*# update foo set i=3;<br /> nextval<br />
---------<br/> 2<br /> (1 row)<br /><br /><br /> test=*# select currval('foo_counter');<br /> currval<br />
---------<br/> 2<br /> (1 row)<br /><br /><br /><br /> Andreas<br /> --<br /> Andreas Kretschmer<br /> Kontakt:
Heynitz:035242/47150, D1: 0160/7141639 (mehr: -> Header)<br /> GnuPG-ID: 0x3FFF606C, privat 0x7F4584DA <a
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am Wed, dem 11.06.2008, um 0:54:55 -0700 mailte Medi Montaseri folgendes: > Thanks...but a difference seems to be that the rule is not specific to update > on a particular col but any col of a row getting updated... > > Thanks Okay, but i havn't an idea. A statement level trigger can't see the the data in NEW and OLD. And a row level trigger fires for every row. > > On Tue, Jun 10, 2008 at 10:21 PM, A. Kretschmer < > andreas.kretschmer@schollglas.com> wrote: Please, no silly top posting with fullquote below, i'm reading from top to bottom. Andreas -- Andreas Kretschmer Kontakt: Heynitz: 035242/47150, D1: 0160/7141639 (mehr: -> Header) GnuPG-ID: 0x3FFF606C, privat 0x7F4584DA http://wwwkeys.de.pgp.net