CREATE TABLE parent (
id INT,
KEY (id)
) ENGINE=InnoDB;
CREATE TABLE child (
id INT,
parent_id INT,
FOREIGN KEY (parent_id) 
REFERENCES parent(id)
ON UPDATE CASCADE
ON DELETE CASCADE
) ENGINE=InnoDB;
INSERT INTO parent VALUES (1), (1), (2), (2);
INSERT INTO child VALUES (1,1), (2,2), (1,1), (2,2);
connection node_2;
DELETE FROM parent WHERE id = 1;
SELECT COUNT(*) = 0 FROM child WHERE id = 1;
COUNT(*) = 0
1
connection node_1;
UPDATE parent SET id = 3 WHERE id = 2;
connection node_2;
SELECT COUNT(*) = 0 FROM child WHERE parent_id = 1;
COUNT(*) = 0
1
SELECT parent_id = 3 FROM child WHERE id = 2;
parent_id = 3
1
1
DROP TABLE child;
DROP TABLE parent;