How do I delete a foreign key constraint in MySQL?

How do I delete a foreign key constraint in MySQL?

Here’s the syntax for DROP FOREIGN KEY statement: ALTER TABLE table_name DROP FOREIGN KEY constraint_name; In the above drop foreign key query, specify table_name from which you want to remove foreign key, in place of table_name. Specify constraint name in place of constraint_name.

Which of the following is used to delete the entries in the referenced table?

FOREIGN KEY (dept name) REFERENCES department . . . ); Which of the following is used to delete the entries in the referenced table when the tuple is deleted in course table? Explanation: The delete “cascades” to the course relation, deletes the tuple that refers to the department that was deleted.

How do you fix #1452 Cannot add or update a child row a foreign key constraint fails?

The problem occurs because you set the foreign key in child table after you insert some data in the child table. Try removing all the data from child table, then set the foreign key and afterwards add/insert the data in table, it will work.

Can you delete a parent row with a foreign key?

The simple way would be to disable the foreign key check; make the changes then re-enable foreign key check. Under your current (possibly flawed) design, you must delete the row out of the advertisers table before you can delete the row in the jobs table that it references.

Can a parent row be deleted in MySQL?

SQLSTATE [23000]: Integrity constraint violation: 1451 Cannot delete or update a parent row: a foreign key constraint fails ( eliapi8. likes, CONSTRAINT likes_post_id_foreign FOREIGN KEY ( post_id) REFERENCES posts ( id )) (SQL: delete from posts where id = 149) Maybe it’s my schema?

Is there a way to remove the foreign key?

Therefore, removing the foreign key is not a sensible option in my opinion. Seems like your Foreign key in Appointments table has On delete: Restrict option. Change the Constraint appointments_user_id_foreign to On delete: Cascade and you should be able to delete Users while preserving Foreign key.

How to preserve a foreign key in phpMyAdmin?

Seems like your Foreign key in Appointments table has On delete: Restrict option. Change the Constraint appointments_user_id_foreign to On delete: Cascade and you should be able to delete Users while preserving Foreign key. When you’re deleting from phpMyAdmin, just uncheck enable foreign key checks at bottom