Question

我正在尝试创建一些代表梦幻足球联赛的桌子，这些桌子本身包含球队，球队本身包含被选中的球员，他们是有统计数据的球员。我现在有一个非常基本的草案，我正在尝试让我的外键工作，但是，当我尝试添加密钥时，我不断收到此错误：

ERROR 1005 (HY000) at line 19: Can't create table 'football_db.PickedPlayers' (errno: 150)

我当然用Google搜索了一下，问题出现了，正如该错误信息所示，该问题与该表上的外键有关。

我可以不添加多组外键吗？还是我选择的外键类型？提前谢谢。

CREATE TABLE football_db.Leagues
    (league_id INT NOT NULL,
     league_name VARCHAR(100),
     PRIMARY KEY (league_id))
    ENGINE=INNODB;
CREATE TABLE football_db.Teams
    (league_id INT NOT NULL,
     team_id INT NOT NULL,
     team_name VARCHAR(100),
     PRIMARY KEY (league_id,team_id),
     FOREIGN KEY (league_id) REFERENCES Leagues(league_id))
    ENGINE=INNODB;
CREATE TABLE football_db.PickedPlayers
    (league_id INT NOT NULL,
     team_id INT NOT NULL,
     player_id INT NOT NULL,
     PRIMARY KEY (player_id),
     FOREIGN KEY (league_id,team_id) REFERENCES Teams(league_id,team_id),
     FOREIGN KEY (player_id) REFERENCES Players(player_id))
    ENGINE=INNODB;
CREATE TABLE football_db.Players
    (player_id INT NOT NULL,
     player_name VARCHAR(50),
     position VARCHAR(10),
     is_free_agent BOOL,
     PRIMARY KEY (player_id))
    ENGINE=INNODB;

Answer 1

在创建此表之前，您正在引用表players，只需在最后位置移动创建表CREATE TABLE football_db.PickedPlayers：

 CREATE TABLE Leagues
(league_id INT NOT NULL,
 league_name VARCHAR(100),
 PRIMARY KEY (league_id))
ENGINE=INNODB;
CREATE TABLE Teams
(league_id INT NOT NULL,
 team_id INT NOT NULL,
 team_name VARCHAR(100),
 PRIMARY KEY (league_id,team_id),
 FOREIGN KEY (league_id) REFERENCES Leagues(league_id))
ENGINE=INNODB;
CREATE TABLE Players
(player_id INT NOT NULL,
 player_name VARCHAR(50),
 position VARCHAR(10),
 is_free_agent BOOL,
 PRIMARY KEY (player_id))
ENGINE=INNODB;
CREATE TABLE PickedPlayers
(league_id INT NOT NULL,
 team_id INT NOT NULL,
 player_id INT NOT NULL,
 PRIMARY KEY (player_id),
 FOREIGN KEY (league_id,team_id) REFERENCES Teams(league_id,team_id),
 FOREIGN KEY (player_id) REFERENCES Players(player_id))
ENGINE=INNODB;

Live working demo

Answer 2

因此，当我打字时，我自己想出了问题。想想我至少会在这里发布我的解决方案，因为其他人可能会遇到同样的问题（非常愚蠢和愚蠢）。

问题是我在PickedPlayers之前创建了Players表，所以它不知道它应该引用Players的哪个外键，因为它不存在爱好。

尝试使用外键创建表时出现错误1005

2 个答案: