> I'd like to do some validations and calculations on a dataset, just
> before the post is performed.
> How can i do that? IB_Query.beforepost,
> IB_datasource.onupdatedate, IB_Datasource.ondatachange?
>
> How can I cancel the post operation if I find an error in the entered
> data? Is there an "abort" method available?

Gunther,

I usually use the OnBeforePost event of the dataset. If you need to
cancel the posting of the record, issue a silent exception, something like
Sysutils.Abort (in Delphi).

HTH
Woody