|
OS: rhel linux as4
DB: oracle10g r2
从oracle在线文档上搜到创建主、外键的语句如下:
ALTER TABLE Dept_tab ADD CONSTRAINT Dept_pkey PRIMARY KEY (deptno);
ALTER TABLE Emp_tab ADD CONSTRAINT Dept_fkey FOREIGN KEY (Deptno) REFERENCES Dept_tab;
于是作了如下实验:
1:添加主键:
SQL> alter table emp add constraint pk-emp primary key (empno);
alter table emp add constraint pk-emp primary key (empno)
*
ERROR at line 1:
ORA-00904: : invalid identifier
SQL> alter table emp add constraint emp_pkey primary key(empno);
Table altered.
SQL> alter table emp add constraint xx_pkey primary key(empno);
Table altered.
2:添加外键
SQL> alter table emp add constraint dept_fkey foreign key(deptno) references dept;
Table altered.
SQL> alter table emp add constraint dept-fkey foreign key (deptno) references dept;
alter table emp add constraint dept-fkey foreign key (deptno) references dept
*
ERROR at line 1:
ORA-00904: : invalid identifier
SQL> alter table emp add constraint xx_fkey foreign key (deptno) references dept;
Table altered.
从实验中得出结论,不管是添加主键,还是添加外键,都必须使用特定的格式 _pkey 或 _fkey
是这样的么 ? 前辈们可否再指点一下!
注意蓝色部分! |
|