炭和石墨材料属于多孔物质,衡量多孔物质的密度有两种测定方法:()。
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You created a view called EMP_DEPT_VU that contains three columns from the EMPLOYEES and DEPARTMENTS tables: EMPLOYEE_ID, EMPLOYEE_NAME AND DEPARTMENT_NAME. The DEPARTMENT_ID column of the EMPLOYEES table is the foreign key to the primary key DEPARTMENT_ID column of the DEPARTMENTS table. You want to modify the view by adding a fourth column, MANAGER_ID of NUMBER data type from the EMPLOYEES tables. How can you accomplish this task?()
ALTER VIEW emp_dept_vu (ADD manager_id NUMBER);
B. MODIFY VIEW emp_dept_vu (ADD manager_id NUMBER);
C. ALTER VIEW emp_dept_vu AS SELECT employee_id, employee_name, department_name, manager_id FROM employee e, departments d WHERE e.department_id = d.department_id;
D. MODIFY VIEW emp_dept_vu AS SELECT employee_id, employee_name, department_name, manager_id FROM employees e, departments d WHERE e.department_id = d.department_id;
E. CREATE OR REPLACE VIEW emp_dept_vu AS SELECT employee_id, employee_name, department_name, manager_id FROM employees e, departments d WHERE e.department_id = d.department_id;
F. You must remove the existing view first, and then run the CREATE VIEW command with a new column list to modify a view.
集团公司《大型、特大型贯通测量工程技术管理规定》大型、特大型贯通测量工程要提前一年(一井贯通工程半年)提出贯通工程测量设计,经总工程师审批后报集团公司审批。
A. 正确
B. 错误
以下关于CSS3的动画说法正确的是()
A. CSS3的动画都是帧动画
B. CSS3的动画类型有三种
CSS3的动画是不可以有交互的
D. CSS3的动画通过webkit-key-frame来预先定义
下列哪种药物不具有降血糖作用()。
A. 茯苓
B. 猪苓
C. 泽泻
D. 茵陈