表示 course表上存在一个名字叫“pk_course”的主键约束 ，它的主键列是 cno,tno的组合列 下面那个同理 表示 SC表上存在一个名字叫“pk_sc”的主键约束 ，它的主键列是 sno,cno的组合列 这是primary key的资料：
建立Student、sc的主码约束 A. LTER TABLE STUDENT ADD CONSTRAINT pk_student_sno PRIMARY KEY NONCLUSTERED (sno); B. LTER TABLE Sc ADD CONSTRAINT pk_sc_snocno PRIMARY KEY (sno,cno); 相关知识点: 试题来源: 解析 A.LTER TABLE STUDENT ADD CONSTRAINT pk_student_sno PRIMARY KEY NONCLUSTERED (...
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));...
百度试题 题目将数据库stu的表sc的sno及cno字段组合定义为主键,约束名称为sc_pk; A. lter table sc B. dd constraint sc_pk primary key (sno,cno) 相关知识点: 试题来源: 解析 A.lter table sc 反馈 收藏
CONSTRAINT PK_Person PRIMARY KEY (ID,LastName) ); Note: In the example above there is only ONE PRIMARY KEY (PK_Person). However, the VALUE of the primary key is made up of TWO COLUMNS (ID + LastName).SQL PRIMARY KEY on ALTER TABLETo...
BackfillingOpen NebulaCloud computingDecision makerIn this work, we present a scheduling mechanism for deadline sensitive task or lease. It is very impelling and challenging to allocate on-demand resources within the deadline rather than rejecting the lease. The work studies the insight of existing ...
*/答案: 1、 select sname from s join sc on(s.sno = sc.sno) join c on (sc.cno = c.cno) where cteacher <> '黎明'; 2、 select sname where sno in (select sno from sc where scgrade < 60 group by sno having count(*) >=2); 3、 select sname from s where sno in (select ...