创建外键SQL

Question

如何创建外键

来自表tGeoAnswers列'locationId'

表tLocations列'id'？

ALTER TABLE 
        tGeoAnswers 
ADD 
        FK_Answer_Location 
FOREIGN KEY 
        (locationId)
REFERENCES 
        tLocations(id)

我正在尝试这个我找到的代码,但是我收到以下错误:

列'FK_Answer_Location'的定义必须包含数据类型

Answer 1

ALTER TABLE tGeoAnswers ADD CONSTRAINT FK_Answer_Location ...

否则,它假定您要添加一个名为的列FK_Answer_Location.

Answer 2

假设MsSql Server/T-SQL,使用ALTER TABLE:

 ALTER TABLE tGeoAnswers
 ADD CONSTRAINT FK_Answer_Location
 FOREIGN KEY (LocationId) REFERENCES tLocation (Id)