Re: Update trigger

On 17 okt, 12:00, phancey <d..._at_2bytes.co.uk> wrote:
> hi,
>
> I need to write a history record for certain fields that change on a
> table. I am not sure whether it is better to write a single AFTER
> UPDATE OF column1,column2,column3 etc trigger that then uses if
> statements to check each specific field whether it has changed OR to
> create an AFTER UPDATE OF column1 ON mytable WHEN nvl(new.column1,-1)
> <> nvl(old.column1,-1) trigger for each column for example.
>
> Is there a performance hit in having 7 AFTER UPDATE triggers defined,
> one for each column I am interested in rather than 1 trigger for all
> 7?
>
> thanks for any help.
>
> Phil

Triggers are parsed on invocation. Obviously 1 parse is less expensive than 7 parses.
If you just use
IF updating('<column name>' then
you wouldn't embark on creating a performance nightmare, which looks syntactically incorrect too.

--
Sybrand Bakker
Senior Oracle DBA