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));...
注意看 constraint 是表示 它是个约束; primary key 表示是个主键约束 所以 constraint pk_course primary key (cno,tno)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 ...
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 (...
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
CONSTRAINTPK_PersonPRIMARYKEY(ID,LastName) ); Note:In the example above there is only ONEPRIMARY KEY(PK_Person). However, the VALUE of the primary key is made up of TWO COLUMNS (ID + LastName). SQL PRIMARY KEY on ALTER TABLE
In 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 backfilling algorithm that is used to schedule ...
deptno desc; (使用order by desc字段 对数据进行降序排列 默认为升序asc); 27、select * from dept where deptno <>10 order by deptno asc; --(我们可以将过滤以后的数据再进行排序) 28、select ename, sal, deptno from emp order by deptno asc, ename desc; --(按照多个字段排序 首先按照deptno升序...