Specifications

Working with validation rules
288 InfoMaker
Understanding validation rules
Validation rules are criteria that a form uses to validate data entered into a
column. They are InfoMaker-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.
Working with validation rules
You work with validation rules in the Database painter and Report painter.
What you do in the
Database painter
In the Database painter, you can:
• Create, modify, and delete named validation rules
The validation rules are stored in the extended attribute system tables.
Once you define a validation rule, it can be used by any column of the
appropriate datatype in the database.
• Assign validation rules to columns and remove them from columns
These rules are used by default when you place the column in a form in the
Report painter.
What you do in the
Form painter
In the Form painter, you can:
• Accept the validation rule assigned to a column in the Database painter
• Create an ad hoc, unnamed rule to use with one specific column
Validation rules and
the extended attribute
system tables
Once you have placed a column that has a validation rule from the extended
attribute system tables in a form, there is no longer any link to the named rule
in the extended attribute system tables.
If the definition of the validation rule later changes in the extended attribute
system tables, the rule for the column in a form will not change.