What is the difference between the CASCADE and SET NULL options in a FOREIGN KEY constraint?
- CASCADE option triggers the automatic deletion of the corresponding rows in the child table when a row in the parent table is deleted.
- SET NULL option updates the foreign key values in the child table to NULL when a row in the parent table is deleted.
- When CASCADE option is used, if a row in the parent table is deleted, then the corresponding rows in the child table will also be deleted.
- When SET NULL option is used, if a row in the parent table is deleted, then the corresponding foreign key values in the child table will be set to NULL.
In CASCADE, the deletion of a parent row will lead to the automatic deletion of the corresponding child rows, whereas in SET NULL, the foreign key values in the child table will be set to NULL when the parent row is deleted. This is crucial in maintaining referential integrity and handling cascading updates and deletes in relational databases.
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