Re: Delphi 2005, Postgresql, ZEOS & optimistic locking

Hi,

Yes, I'm sure this kind of feature is application-based. There is nothing in the driver itself. If I'm not wrong, MS Access uses a timestamp column to check if the record was updated meanwhile, or the column values if not timestamp is available. This might be true only with a MS SQL Database, though.

I'll try doing something similar in a Delphi event-handler.

Thanks, bye

Philippe

-----Message d'origine-----
De : Tony Caduto [mailto:tony_caduto(at)amsoftwaredesign(dot)com]
Envoyé : jeudi, 12. mai 2005 21:07
À : Philippe Lang
Cc : pgsql-general(at)postgresql(dot)org
Objet : Re: [GENERAL] Delphi 2005, Postgresql, ZEOS & optimistic locking

Why not just add a onenter event handler to the forms field in question and just check the data before they edit it.
If it's different update the field with the most current data.

Access probably just does something similar under the hood for you.
I don't think that's a feature of the ODBC driver or is it?

If it is you could always use the ODBC driver from Delphi as well.

>
> With Dephi/BDE/ODBC, this is different: as soon as you try updating a field that has been modified by someone else meanwhile, the field is automatically updated for you before you start making your own changes, and of course before you try to commit them. That's fine too. I would have preferred an error personnally.
>
> Is there a way to do the same with ZEOS? Or maybe is there another mecanism that could be used to do optimistic locking? Some kind of "long transactions", in the database server?
>
> Philippe Lang
>