sql - oracle 引用列的数量必须与引用的列匹配

Question

我一直收到一条错误消息，外键引用列表中的列数不等于引用列表中的列数。

这是我得到错误的那一行。

      foreign key(EID, Lastname, Firstname, Midinitial) references employee,

有谁知道我为什么会收到这个错误？

create table employee(
  EID varchar(20) primary key,
  Lastname varchar(20),
  Firstname varchar(20),
  Midinitial char(1),
  gender char(1),
  street varchar(20),
  city varchar(20)
);

create table works(
  EID varchar(20) primary key,
  Lastname varchar(20),
  Firstname varchar(20),
  Midinitial char(1),
  company_name varchar(20),
  salary numeric(5,0),
  foreign key(EID, Lastname, Firstname, Midinitial) references employee,
  foreign key(company_name) references company
);

create table company(
  company_name varchar(20) primary key,
  city varchar(20),
  foreign key(city)references employee
);

Answer 1

您只需要员工的主键：

foreign key(EID) references employee