MySQL ON DELETE CASCADE not work

Question

i have two table (type innoDb) why when i deleting main table row like

+note(im using arch os so my database server type is maria db)

DELETE FROM buildings 
WHERE
    building_no = 2;

relation table rows dont delete ???

CREATE TABLE buildings (
    building_no INT PRIMARY KEY AUTO_INCREMENT,
    building_name VARCHAR(255) NOT NULL,
    address VARCHAR(255) NOT NULL
);

CREATE TABLE rooms (
    room_no INT PRIMARY KEY AUTO_INCREMENT,
    room_name VARCHAR(255) NOT NULL,
    building_no INT NOT NULL,
    FOREIGN KEY (building_no)
        REFERENCES buildings (building_no)
        ON DELETE CASCADE
);

Answer 1

This syntax works for me on MySQL database but i can't see issues in your query too

CREATE TABLE  `rooms` (
  room_no INT PRIMARY KEY AUTO_INCREMENT,
  room_name VARCHAR(255) NOT NULL,
  building_no INT NOT NULL,
  CONSTRAINT `FK_rooms_1` FOREIGN KEY (`building_no`) REFERENCES `buildings` 
  (`building_no`) ON DELETE CASCADE
) ENGINE=InnoDB;

or add the constraint after table creation

ALTER TABLE `rooms`
  ADD CONSTRAINT `FK_rooms_1` FOREIGN KEY (`building_no`) REFERENCES `buildings` (`building_no`) ON DELETE CASCADE ON UPDATE CASCADE;