Re: Trigger

Andy Samuel wrote:

> How do I create a trigger on a table if a certain row is updated ?
> For example, a table called DefaultValue with :
> ModuleId char(10),
> FieldId char(10),
> DefVal char(3)
>
> If I update the table 'update DefaultValue set defval='OFF' where
> FieldId='MODULESTATUS' then it will fire the event.

Here is an example of one I use

CREATE FUNCTION "update_seqno" ( ) RETURNS opaque AS '
BEGIN
new.seqno = nextval(''cdrseqno'');
new.status = ''U'';
return new;
END;' LANGUAGE 'plpgsql';

CREATE TRIGGER "updseq_no" BEFORE INSERT ON "accounting" FOR EACH ROW
EXECUTE PROCEDURE "update_seqno" ();

seqno and status are attributes of the accounting-table that do not get set
by the insert statement I use, so the trigger provides the sequence number
from the defined sequence 'cdrseqno' and sets a default status on it.

You can define triggers on [ BEFORE/AFTER ] [ INSERT/DELETE/UPDATE ] .
This all is documented in the docs that come with PostgreSQL. Pay attention
to the double ' when you create functions/triggers.

Regards,

Feite

>
>
> Thank you in advance
> Andy
>
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Feite Brekeveld
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