mysql alter table add column and foreign key code example
Example 1: alter table add foreign key mysql
ALTER TABLE orders
ADD
FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE;
Example 2: alter table add column and foreign key mysql
ALTER TABLE database.table
ADD COLUMN columnname INT DEFAULT(1),
ADD FOREIGN KEY fk_name(fk_column) REFERENCES reftable(refcolumn) ON DELETE CASCADE;