Parent key enforcement

 

The rules that you specify for a referential constraint determine how the database processes the delete and update operations on the parent key. The system enforces the unique attribute of a parent key on all parent file I/O.

• Enforcement of delete rules
  When you delete a record from a parent file, the system checks the dependent file for any dependent records (matching non-null foreign key values). If the system finds any dependent records, the delete rule determines the action to be taken.

• Enforcement of update rules
  When the system updates a parent key in a parent file, it checks for any dependent records (matching non-null foreign values) in the dependent file. If the system finds any dependent records, the update rule for the constraint relationship determines the action to be taken.

 

Parent topic:

Referential integrity enforcement