When users enter data in a form, 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 Report painter.
InfoMaker uses validation rules when you enter data:
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Directly in the database using the Database painter
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In a form
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.
Validation rules are criteria that a form uses to validate data entered into a column. They are IM-specific and therefore not enforced by the DBMS. Validation rules apply to forms (which support updating) but not to reports.
Validation rules assigned in the Database painter are used by default when you place columns in a form. You can override the default rules in the Report painter.
A validation rule is an expression that evaluates to either "true" or "false". If the expression evaluates to "true" for an entry into a column, InfoMaker accepts the entry. If the expression evaluates to "false", the entry is not accepted and an error message is displayed. You can customize the message displayed when a value is rejected.
