Re: Trigger to identify which column(s) updated - Mailing list pgsql-sql

From Vishal Kashyap @ [Sai Hertz And Control Systems]
Subject Re: Trigger to identify which column(s) updated
Date
Msg-id 400B08AC.8040607@sancharnet.in
Whole thread Raw
In response to Trigger to identify which column(s) updated  ("Jack Kerkhof" <jack.kerkhof@guest-tek.com>)
List pgsql-sql
Dear Jack ,

>I suspect that the function would look something like;
>
>CREATE FUNCTION FIND_CHANGED_COLUMNS() RETURNS OPAQUE AS '
>BEGIN
>
>   -- FOR EACH COLUMN IN THE RECORD:
>      -- IF ( NEW COLUMNx <> OLD COLUMNx)
>         -- LOG THE RECORD PRIMARY KEY, COLUMN NAME, OLD VALUE
>
>   RETURN NEW;
>END;
>' LANGUAGE 'plpgsql';
>  
>

Instead of using a trigger use a rule as
<code>


</code>
CREATE RULE log_allthat  AS ON UPDATE TO table_to_scan  WHERE 
((NEW.coloum_1 !=  old.NEW.coloum_1) OR (NEW.coloum_2 !=  
old.NEW.coloum_2)) OR (MORE COLUMNS DO
INSERT INTO log_changes_table (

PRIMARY_KEY,COLUMN_NAME,OLD_VALUE

) VALUES (

OLD.PRIMARY_KEY,OLD.COLUMN_NAME,OLD.OLD_VALUE

);


Yes you will have to create a table as log_changes_table or any name you 
fancy such that data could be loged
</code>

Kindly shoot back if this helps.

-- 
Regards,
Vishal Kashyap

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