Answer:
Follows are the matching to this question:
Explanation:
While time-consuming or prone to errors mechanical adjustments to both the referential, databases could be configured with four measures to engine violations. The restricted action causes the insert, update, and removes to only be denied. Set Null to NULL sets the invalid external key, whereas Set Default to a specific core consideration specified in SQL sets a default foreign key. Its Cascade operation spreads the main changes in external keys.