Bagaimana cara menghapus semua baris referensi secara otomatis jika baris induk dihapus di mysql?

Anda dapat melakukannya dengan ON DELETE CASCADE .

ALTER TABLE childTable
  ADD CONSTRAINT `FK_key` FOREIGN KEY (`childColumnName`) 
  REFERENCES parentTable(`parentColumnName`) ON UPDATE CASCADE ON DELETE CASCADE

ATAU

Buat AFTER DELETE TRIGGER di tabel induk . Tambahkan kueri DELETE dari tabel anak.

DELIMITER $$

CREATE
    TRIGGER `tn_aur_department_master` AFTER DELETE ON `tn_parentTable` 
    FOR EACH ROW BEGIN
        DELETE FROM childTable WHERE parentId = old.parentId;
    END;
$$

DELIMITER ;