MySQL 错误 1215 - 外键(日期类型)到主键(日期类型)

Question

我正在尝试将 PostDate 从 Speech 引用到从 P_ASSIGNMENT 的 PostDate，但它给我 “错误 1215:无法添加外键约束”。 我目前正在 MySQL Workbench 上开发 InnoDB。

这是我的 SQL 代码:

CREATE TABLE P_ASSIGNMENT
(StaffID int not null,
 JobID int not null,
 PostDate date not null,
 EndDate date,
 CONSTRAINT P_Assignment_pk PRIMARY KEY (StaffID, JobID, PostDate),
);

CREATE TABLE SPEECH
 (EventName varchar(100) not null,
  EventDate date not null,
  OrderNum int not null,
  ContentAbst varchar(250),
  Contact int not null,
  Presenter int not null,
  JobID int not null,
  PostDate date not null,
 CONSTRAINT Speech_pk PRIMARY KEY (EventName, EventDate, OrderNum),
 CONSTRAINT Speech_fk3 FOREIGN KEY (Presenter) REFERENCES P_ASSIGNMENT (StaffID),
 CONSTRAINT Speech_fk4 FOREIGN KEY (JobID) REFERENCES P_ASSIGNMENT (JobID),
 CONSTRAINT Speech_fk5 FOREIGN KEY (PostDate) REFERENCES P_ASSIGNMENT(PostDate)
);

Answer 1

这是一个单一复合外键。语法是:

CREATE TABLE SPEECH
 (EventName varchar(100) not null,
  EventDate date not null,
  OrderNum int not null,
  ContentAbst varchar(250),
  Contact int not null,
  Presenter int not null,
  JobID int not null,
  PostDate date not null,
 CONSTRAINT Speech_pk PRIMARY KEY (EventName, EventDate, OrderNum),
 CONSTRAINT Speech_fk3 FOREIGN KEY (Presenter, JobID, PostDate) -- fix here
   REFERENCES P_ASSIGNMENT (StaffID, JobID, PostDate)
);

为了说明这一点，您没有三个外键。你有一个外键。该外键是复合键，因为它包含三列。