ALTER TABLE feature_gene_id ADD FOREIGN KEY (id) REFERENCES feature(id) ON DELETE CASCADE;
ALTER TABLE feature_names ADD FOREIGN KEY (id) REFERENCES feature(id) ON DELETE CASCADE;
ALTER TABLE feature_db_xref ADD FOREIGN KEY (id) REFERENCES feature(id) ON DELETE CASCADE;
ALTER TABLE feature_introns ADD FOREIGN KEY (id) REFERENCES feature(id) ON DELETE CASCADE;
ALTER TABLE feature_exons ADD FOREIGN KEY (id) REFERENCES feature(id) ON DELETE CASCADE;
ALTER TABLE feature_ec_number ADD FOREIGN KEY (id) REFERENCES feature(id) ON DELETE CASCADE;