A. The DESCRIBE DEPT statement displays the structure of the DEPT table.
B. The ROLLBACK statement frees the storage space occupies by the DEPT table.
C. The DESCRIBE DEPT statement returns an error ORA-04043: object DEPT does not exist.
D. The DESCRIBE DEPT statement displays the structure of the DEPT table only if there is a COMMIT statement introduced before the ROLLBACK statement.
第1题:
A.The DESCRIBE DEPT statement displays the structure of the DEPT table.
B.The ROLLBACK statement frees the storage space occupied by the DEPT table.
C.The DESCRIBE DEPT statement returns an error ORA-04043: object DEPT does not exist.
D.The DESCRIBE DEPT statement displays the structure of the DEPT table only if there is a COMMIT statement introduced before the ROLLBACK statement.
第2题:
部门DEPT(Deptno,Name,Tel,Leader)和职工EMP(Empno,Name,Sex,Address, Deptno)实体集,若一个职工只能属于一个部门,部门负责人Leader是一个职工。关系 DEPT和EMP的外码分别为(30);下图中a、b处的实体名分别为(31)。
A.Deptno、Empno
B.Name、Deptno
C.Leader、Deptno
D.Name、Address
第3题:
【单选题】对于建立在数据库上的DDL触发器,常用的激活DDL触发器的事件不包括()
A.Create_Table,Alter_Table,Drop_Table
B.Create_View,Alter_View,Drop_View
C.Create_Procedure,Alter_Procedure,Drop_Procedure
D.Rollback
第4题:
● 部门DEPT(Deptno, Name, Tel, Leader) 和职工EMP(Empno, Name, Sex, Address, Deptno) 实体集,若一个职工只能属于一个部门,部门负责人 Leader 是一个职工。关系DEPT和EMP的外码分别为 (30) ;下图中a、b处的实体名分别为 (31) 。
(30)
A. Deptno、Empno
B. Name、 Deptno
C. Leader、Deptno
D. Name、 Address
(31)
A. DEPT、Empno
B. DEPT、EMP
C. EMP、Deptno
D. EMP、DEPT
第5题:
列出所有部门的职工人数(包括没有职工的部门) ()。
A.select dept.deptno,dname,count(emp.empno) from emp,dept where emp.deptno=dept.deptno group by dept.deptno,dname;
B.select dept.deptno,dname,count(emp.empno) from emp,dept where emp.deptno()=dept.deptno group by dept.deptno,dname;
C.select dept.deptno,dname,count(emp.empno) from emp,dept where emp.deptno=dept.deptno() group by dept.deptno,dname;
D.select dept.deptno,dname,count(emp.empno) from emp,dept where emp.deptno(