Understanding the Enforce Rule and Blanks Allowed Check Boxes

The Column Relationships program (P00421) has two check boxes:

• Enforce Rule

• Blanks Allowed

These check boxes control the default rules that apply to the destination columns that you define for a column set. The system uses the rules to update the destination values in the F0006 and F5201 tables. This table discusses the check boxes and default rules:

Check Boxes	Default Rule
Enforce Rule	If the Enforce Rule check box is selected, the destination column is protected from input in the entry program. (The destination column is protected from input even if it later becomes a basis column in the column set.) If a value for the destination column exists in the table, in update mode the system overrides that value with the value defined in the Value Relationships table (F00422). If a blank value is valid and the Blanks Allowed check box is selected for the destination column, the system overrides the existing value in the table. If the Enforce Rule check box is not selected, the destination column allows you to enter non-blank values. If a value for the destination column exists, the system does not override that value because the Enforce Rule check box is not selected. Instead, the system skips the destination column and the default rules continue with the first destination column that is either blank or has the Enforce Rule selected.
Blanks Allowed	If the Blanks Allowed check box is selected, blank values are valid for the destination column. This check box is valid only for strings and characters, and not for math numeric values. Note: The Blanks Allowed check box is only valid if the Enforce Rule check box is selected.