Examine the structure of the EMPLOYEES and DEPARTMENTS tables:EMPLOYEESEMPLOYEE_ID NUMBERDEPARTMENT_ID NUMBERMANAGER_ID NUMBERLAST_NAME VARCHAR2(25)DEPARTMENTSDEPARTMENT_ID NUMBERMANAGER_ID NUMBERDEPARTMENT_NAME VARCHAR2(35)LOCATION_ID NUMBERYou want to create a report displaying employee last names, department names, and locations. Which query should you use to create an equi-join?()
A. SELECT last_name, department_name, location_id FROM employees , department ;
B. SELECT employees.last_name, departments.department_name, departments.location_id FROM employees e, departments D WHERE e.department_id = d.department_id;
C. SELECT e.last_name, d.department_name, d.location_id FROM employees e, departments D WHERE manager_id = manager_id;
D. SELECT e.last_name, d.department_name, d.location_id FROM employees e, departments D WHERE e.department_id = d.department_id;
第1题:
( 2 )现有如下两个关系模式:
Employees ( Eid , Name , DeptNO )
Departments ( DeptNO , DeptName , TotalNumber )
Employees 关系模式描述了职工编号、姓名和所在部门编号; Departments 关系模式描述了部门编号、名称和职工总人数。
请 按 SQL Serve r 所采用 的 Tansact — SQ L 语法格式编写实现具有功能的后触发型触发器 : 每当在Employee s表中插入一行数据时,相应部门的职工总人数就加 1 。( 10 分)
第2题:
已知关系模式R的全部属性集U={A,B,C,D,E,G}及函数依赖集:
F=(AB→C,C→A,BC→D,ACD→B,D→EG,BE→C,CG→BD,CE→AG}求属性集闭包(BD)+
(2) 现有如下两个关系模式:
Employees(Eid,Name,DeptNO)
Departments(DeptNO,DeptName,TotalNumber)
Employees关系模式描述了职工编号、姓名和所在部门编号;Departments关系模式描述了部门编号、名称和职工总
第3题:
Nothing in these Rules shall ______ any vessel,or the owner,master or crew thereof,from the consequences of any precaution which may be required by the ordinary practice of seaman,or by the special circumstances of the case.
A.exonerate
B.exhaust
C.exercise
D.examine
第4题:
第5题:
检查
A.expect
B.except
C.excuse
D.examine
第6题: