What are foreign key constraints in SQL?

What are foreign key constraints in SQL?

Foreign key constraints are rules that maintain referential integrity between two tables in a database.

Can you give me an example of how to create a foreign key constraint?

Sure! You can create a foreign key constraint using the following SQL syntax: ALTER TABLE child_table ADD CONSTRAINT fk_name FOREIGN KEY (column_name) REFERENCES parent_table (column_name);

What happens if I try to delete a record that is referenced by a foreign key?

If you try to delete a record that is referenced by a foreign key, the database will prevent the deletion to maintain referential integrity, unless you specify ON DELETE CASCADE.

How can I remove a foreign key constraint?

You can remove a foreign key constraint using the syntax: ALTER TABLE table_name DROP CONSTRAINT fk_name;