在看《Learning SQL》第二版，
慢慢打实SQL的基础。
建表一：
CREATE TABLE person (person_id SMALLINT UNSIGNED, fname VARCHAR(20), lname VARCHAR(20), gender ENUM('M', 'F'), birth_date DATE, street VARCHAR(30), city VARCHAR(20), state VARCHAR(20), country VARCHAR(20), postal_code VARCHAR(20), CONSTRAINT pk_person PRIMARY KEY (person_id) );
建表二：
CREATE TABLE favorite_food (person_id SMALLINT UNSIGNED, food VARCHAR(20), CONSTRAINT pk_favorite_food PRIMARY KEY (person_id, food), CONSTRAINT fk_fav_food_person_id FOREIGN KEY (person_id) REFERENCES person (person_id) );
