在看《Learning SQL》第二版，
慢慢打实SQL的基础。
建表一：
), lname ), gender ENUM(), city ), state ), country ), postal_code ), CONSTRAINT pk_person PRIMARY KEY (person_id) );
建表二：
), CONSTRAINT pk_favorite_food PRIMARY KEY (person_id, food), CONSTRAINT fk_fav_food_person_id FOREIGN KEY (person_id) REFERENCES person (person_id) );