Question

我在创建此表后尝试添加外键

Create table Member
(
memeberID int Not null Primary Key,
mebershipID int Not null,
group_id  int not NULL,
Dutycode int not null,
MemberRole varchar(255),
name varchar(255),
last_joined date,
DOB date,
address varchar(255),

CONSTRAINT fk_DutCodes FOREIGN KEY (Dutycode)
REFERENCES RaceManagementDuty(Dutycode),


CONSTRAINT fk_GrMemeberinMemeber FOREIGN KEY (group_id)
REFERENCES Group_member(group_id),

CONSTRAINT fk_Mebersids FOREIGN KEY (mebershipID)
REFERENCES Membership(mebershipID)
)

我想创建的外键是使用Alter表的Sailnumber：

ALTER TABLE会员添加外键（帆船号码）参考船（帆船）

帆船是桌船的主要钥匙，如下所示

Create table Boat
(
sailnumber  int not null Primary Key,
mebershipID  int not NULL,
group_id int not NULL,
sizeOfBoat decimal(5,2),
weight decimal(5,2),
sailarea integer,
numberOfCrew integer,
portsmouthNumber integer,

CONSTRAINT fk_MebersidsBoat FOREIGN KEY (mebershipID)
REFERENCES Membership(mebershipID),


CONSTRAINT fk_GrMemeberinMemebers FOREIGN KEY (group_id)
REFERENCES Group_member(group_id)
)

但是，我收到此错误SQL错误：ORA-00904：＆＃34; SAILNUMBER＆＃34;：无效的标识符，我不知道为什么我能得到任何人都可以告诉我我在哪里＃39;我错了？

Answer 1

您需要将Sailnumber列添加到Member表中（在执行add foreign key查询之前）

ALTER TABLE Member ADD sailnumber INT NOT NULL;
ALTER TABLE Member ADD FOREIGN KEY (sailnumber) REFERENCES Boat(sailnumber);

或在一个查询中：

ALTER TABLE member 
ADD sailnumber INT NOT NULL CONSTRAINT sailnumber REFERENCES boat(sailnumber);

SQL错误：ORA-00904：标识符无效

1 个答案: