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.
- No Action. If the system finds any dependent records, it returns a constraint violation, does not update any records.
- Restrict. The system performs the same as above, but enforcement is immediate.