首先您需要在表orderbook
中添加新列。
ALTER TABLE orderbook
ADD payment_request_id INT(10) unsigned AFTER ID;
ALTER TABLE orderbook
ADD CONSTRAINT fk_orderbook FOREIGN KEY (payment_request_id)
REFERENCES payment_request (id);
参考:
错误代码:1215。无法添加外键约束
。 - ArefeCREATE TABLE Orders (
OrderID int NOT NULL,
OrderNumber int NOT NULL,
PersonID int,
PRIMARY KEY (OrderID),
FOREIGN KEY (PersonID) REFERENCES Persons(PersonID)
);
或通过修改表格:
ALTER TABLE Orders
ADD FOREIGN KEY (PersonID) REFERENCES Persons(PersonID);
还可以参考这个教程。