connection node_2;
connection node_1;
CREATE TABLE grandparent (
id INT NOT NULL PRIMARY KEY
) ENGINE=InnoDB;
CREATE TABLE parent (
id INT NOT NULL PRIMARY KEY,
grandparent_id INT,
FOREIGN KEY (grandparent_id)
REFERENCES grandparent(id)
ON UPDATE CASCADE
) ENGINE=InnoDB;
CREATE TABLE child (
id INT NOT NULL PRIMARY KEY, 
grandparent_id INT,
FOREIGN KEY (grandparent_id)
REFERENCES parent(grandparent_id)
ON UPDATE CASCADE
) ENGINE=InnoDB;
INSERT INTO grandparent VALUES (1),(2);
INSERT INTO parent VALUES (1,1), (2,2);
INSERT INTO child VALUES (1,1), (2,2);
connection node_2;
UPDATE grandparent SET id = 3 WHERE id = 1;
connection node_1;
SELECT COUNT(*) = 1 FROM parent WHERE grandparent_id = 3;
COUNT(*) = 1
1
SELECT COUNT(*) = 1 FROM child WHERE grandparent_id = 3;
COUNT(*) = 1
1
DROP TABLE child;
DROP TABLE parent;
DROP TABLE grandparent;
