The delete rule controls how the delete operations are performed against a parent table participating in a referential integrity constraint. The four possible behaviors with a delete rule are as follows:
- ON DELETE CASCADE: This ensures that whenever a record from the parent table of a referential integrity constraint is deleted, all dependent records in the child table that have matching primary key values in their foreign key are deleted as well.
- ON DELETE SET NULL: This ensures that whenever a record from the parent table of a referential integrity constraint is deleted, all the dependent records in the child table that have matching primary key values in their foreign key are set to NULL. For ...
