MySQL：无法创建表（errno = 150）

Question

我正在尝试创建SEASON和PLAYER表，如下所示：

CREATE TABLE SEASON(
    season_id INT NOT NULL,    #primary key can't be NULL
    start_date DATE,
    end_date DATE)
ENGINE = INNODB;

CREATE TABLE PLAYER(
    player_id INT NOT NULL,
    first_name VARCHAR(15) NOT NULL,
    last_name VARCHAR(15) NOT NULL,
    position VARCHAR(15),
    first_season_id INT,
    last_season_id INT,
    height_feet INT,
    height_inch INT,
    weight INT,
    college VARCHAR(30),
    birthday DATE,
    PRIMARY KEY(player_id),
    FOREIGN KEY(first_season_id) REFERENCES SEASON(season_id)
       ON DELETE CASCADE   ON UPDATE CASCADE,
    FOREIGN KEY(last_season_id) REFERENCES SEASON(season_id)
       ON DELETE CASCADE   ON UPDATE CASCADE,
    CHECK (height_feet > 0 AND height_inch >= 0 AND weight > 0))
ENGINE=INNODB;

我得到错误，我不能创建PLAYER表但我真的不明白为什么:(

Answer 1

尝试这个：

CREATE TABLE SEASON( season_id INT NOT NULL, start_date DATE, end_date DATE, PRIMARY KEY(season_id)) ENGINE = INNODB;

CREATE TABLE PLAYER( player_id INT NOT NULL, first_name VARCHAR(15) NOT NULL, last_name VARCHAR(15) NOT NULL, position VARCHAR(15), first_season_id INT, last_season_id INT, height_feet INT, height_inch INT, weight INT, college VARCHAR(30), birthday DATE, PRIMARY KEY(player_id), FOREIGN KEY(first_season_id) REFERENCES SEASON(season_id) ON DELETE CASCADE ON UPDATE CASCADE, FOREIGN KEY(last_season_id) REFERENCES SEASON(season_id) ON DELETE CASCADE ON UPDATE CASCADE, CHECK (height_feet > 0 AND height_inch >= 0 AND weight > 0)) ENGINE=INNODB;

它将season_id添加为主键。

Answer 2

使引用列成为主键，外键需要引用主键或唯一键。

http://sqlfiddle.com/#!2/4c60e