CREATE OR REPLACE TEMPORARY TABLE tItemShelving
	(PRIMARY KEY (id))
	ENGINE = MEMORY
	SELECT ish.id, s.id shelvingFk
		FROM shelving s
			JOIN itemShelving ish ON ish.shelvingFk = s.code;

ALTER TABLE vn.itemShelving DROP FOREIGN KEY itemShelving_fk2,
	MODIFY COLUMN shelvingFk int(11) NOT NULL;

UPDATE itemShelving ish
		JOIN tItemShelving tis ON tis.id = ish.id
	SET ish.shelvingFk = tis.shelvingFk;

DROP TEMPORARY TABLE tItemShelving;

ALTER TABLE vn.itemShelving
	ADD CONSTRAINT itemShelving_shelving_FK FOREIGN KEY (shelvingFk) REFERENCES vn.shelving(id)
		ON DELETE RESTRICT
		ON UPDATE CASCADE;