외래키 제한 때문에 삽질하다가 찾아낸 sql 샘플 참조 : http://www.mysqltutorial.org/mysql-on-delete-cascade/ CREATE TABLE buildings ( building_no INT(11) NOT NULL AUTO_INCREMENT, building_name VARCHAR(255) NOT NULL, address VARCHAR(355) NOT NULL, PRIMARY KEY (building_no) ) ENGINE=INNODB; CREATE TABLE rooms ( room_no INT(11) NOT NULL AUTO_INCREMENT, room_name VARCHAR(255) NOT NULL, building_no INT(11) NOT NULL, PRIMA..