--- Michael Fuhr <mike@fuhr.org> wrote:
> On Thu, Jan 26, 2006 at 02:22:37PM -0800,
> operationsengineer1@yahoo.com wrote:
> > i set up an update statement to update a unit's
> status
> > from incomplete to completed.
> >
> > however, pgsql doesn't kick out an error message
> when
> > i try to update something that doesn't exist.
>
> The database has no way of knowing that a certain
> number of rows
> updated (zero in your case) represents an error;
> that's something
> the application knows. An update that affects zero
> rows is perfectly
> legitimate in many applications.
>
> > i'm thinking about running a select to check the
> > existence of the serial number before running the
> > update. that way, i can check that the serial 1.
> > exists and 2. hasn't already been updated and,
> based
> > on the result, kick out a message to the user as
> > appropriate.
>
> Your API should provide a way to get the number of
> rows updated.
> What language and database interface are you using?
>
> --
> Michael Fuhr
>
ADOdb - and thanks for the idea.
i can run the query, check for rows updated and then
do whatever makes sense from that point.
a zero row update can still mean two things, though -
the serial doesn't exist or the serial exists, but
already has been updated to the new value. i need to
decide if that distinction will be important enough to
differentiate the error messages.
thanks again.
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