Re: Trigger problem - Mailing list pgsql-sql

From Jan Wieck
Subject Re: Trigger problem
Date
Msg-id 40C7BD04.1040105@Yahoo.com
Whole thread Raw
In response to Re: Trigger problem  (Mike Rylander <miker@purplefrog.com>)
List pgsql-sql
On 6/8/2004 2:57 PM, Mike Rylander wrote:

> kasper wrote:
> 
>> Hi guys
>> 
>> Im tryint to make a trigger that marks a tuble as changed whenever someone
>> has updated it
>> 
>> my table looks something like this
>> 
>> create table myTable (
>>     ...
>>     changed boolean;
>> )
>> 
>> now ive been working on a trigger and a sp that looks like this, but it
>> doesnt work...
>> 
>> create function myFunction returns trigger as '
>>     begin
>>         new.changed = true;
> 
> The line above is using the SQL equaliy opperator, you want the assignment
> operator:
> 
>   :=
> 
> as in 
> 
>         new.changed := true;

PL/pgSQL accepts both. What's wrong is that it's an AFTER trigger, which 
is fired AFTER the new row is already stored on disk and thus cannot 
change it any more.


Jan

> 
>>         return new;
>>     end;
>> ' language 'plpgsql';
>> 
>> create trigger myTrigger
>> after update on lektioner
>> for each row
>> execute procedure myFunction();
>> 
>> 
>> the code compiles, runs, and doesnt whine about anything, but nothing
>> changes...
>> 
>> any ideas??
>> 
>> - Kasper
> 
> -miker
> 
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 7: don't forget to increase your free space map settings


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