Deleting from a MySQL table with foreign key constraints

Question

I have two tables, with some data loaded in it and the two reference each other. Table B references the primary key of Table A. I manually attempt to delete some table rows from

Answer 1

Unfortunately, the automatic deletion that you think should happen does not happen. You would need to manually delete the rows in Table B that contain the ID from the row in Table A that you wish to remove.

Try adding ON DELETE CASCADE to your foreign key column definition in Table B.

If you are using Hibernate, or some other ORM tool, it would have a "cascade" mechanism that would handle this automatically. But here since you are interfacing with the database directly, you must keep in mind that a row cannot be deleted if the ID of said row exists in any other table as a foreign key (as in your case, the primary key of A exists in some of the rows in B). Unless of course you specify the ON DELETE CASCADE property.