How to delete rows in tables that contain foreign keys to other tables

Question

Suppose there is a main table containing a primary key and there is another table which contains a foreign key to this main table. So if we delete the row of main table it w

Answer 1

You can alter a foreign key constraint with delete cascade option as shown below. This will delete chind table rows related to master table rows when deleted.

ALTER TABLE MasterTable
ADD CONSTRAINT fk_xyz 
FOREIGN KEY (xyz) 
REFERENCES ChildTable (xyz) ON DELETE CASCADE