数据库原理课后题答案⏺CONSTRAINT PK_SC PRIMARY KEY (Deptno));CREATE TABLE EMP(Empno NUMBER(4) primary key,Ename VARCHAR(10),Age NUMBER(2),CONSTRAINT C1 CHECK (Aage < =60),Job VARCHAR(9),Sal NUMBER(7,2),Deptno NUMBER(2),CONSTRAINT FK_DEPTNOFOREIGN KEY(Deptno)REFERENCES DEPT(Deptno));...
(100) 删除字段 alter table table_name drop column column_name 添加主键 alter table table_name add constraint pk_name primary key(column_id) 删除主键 alter table table_name drop constraint pk_name 添加外键 alter table table_name add constraint fk_name foreign key(column_...