When users enter data in a DataWindow object, you want to be sure the data is valid before using it to update the database. Validation rules provide one way to do this.
You usually define validation rules in the Database painter. To use a validation rule, you associate it with a column in the Database painter or DataWindow object painter.
Another technique
You can also perform data validation through code tables,
which are implemented through a column's edit style.
For more information, see “About edit styles”.
