Examine the structure of the EMPLOYEES table: EMPLOYEE_……

单项选择题Examine the statement:Create synonym emp for hr. employees;What happens when you issue the statement?（）

A. An error is generated.
B. You will have two identical tables in the HR schema with different names.
C. You create a table called employees in the HR schema based on you EMP table.
D. You create an alternative name for the employees table in the HR schema in your own schema.

单项选择题Which statement accomplish this?（）

A. CREATE TABLE orders ( order_id NUMBER (10), customer_id NUMBER (8), order_status VARCHAR2 (10), date_ordered DATE = SYSDATE);
B. CREATE TABLE orders ( order_id NUMBER (10), customer_id NUMBER (8), order_status VARCHAR2 (10), date_ordered DATE DEFAULT SYSDATE);
C. CREATE OR REPLACE TABLE orders ( order_id NUMBER (10), customer_id NUMBER (8), order_status VARCHAR2 (10), date_ordered DATE DEFAULT SYSDATE);
D. CREATE OR REPLACE TABLE orders ( order_id NUMBER (10), customer_id NUMBER (8), order_status NUMBER (10), date_ordered DATE = SYSDATE);
E. CREATE TABLE orders ( order_id NUMBER (10), customer_id NUMBER (8), order_status NUMBER (10), date_ordered DATE = SYSDATE);
F. CREATE TABLE orders ( order_id NUMBER (10), customer_id NUMBER (8), order_status NUMBER (10), date_ordered DATE DEFAULT SYSDATE);

单项选择题The EMPLOYEES table has these columns: Management wants to add a default value to the SALARY column. You plan to alter the table by using this SQL statement: What is true about your ALTER statement?（）

A. Column definitions cannot be altered to add DEFAULT values.
B. A change to the DEFAULT value affects only subsequent insertions to the table.
C. Column definitions cannot be altered at add DEFAULT values for columns with a NUMBER data type.
D. All the rows that have a NULL value for the SALARY column will be updated with the value 5000.

多项选择题Exhibit The COMMISSION column shows the monthly commission earned by the employee. Which two tasks would require subqueries or joins in order to be performed in a single step? （）

A. listing the employees who earn the same amount of commission as employee 3
B. finding the total commission earned by the employees in department 10
C. finding the number of employees who earn a commission that is higher than the average commission of the company
D. listing the departments whose average commission is more that 600
E. listing the employees who do not earn commission and who are working for department 20 in descending order of the employee ID 
F. listing the employees whose annual commission is more than 6000

单项选择题User Mary has a view called EMP_DEPT_LOC_VU that was created based on the EMPLOYEES, DEPARTMENTS, and LOCATIONS tables. She has the privilege to create a public synonym, and would like to create a synonym for this view that can be used by all users of the database.Which SQL statement can Mary use to accomplish that task?（）

A. CREATE PUBLIC SYNONYM EDL_VU ON emp_dept_loc_vu
B. CREATE PUBLIC SYNONYM EDL:VU FOR mary (emp_dept_loc_vu);
C. CREATE PUBLIC SYNONYM EDL_VU FOR emp _dept_loc_vu;
D. CREATE SYNONYM EDL_VU ON emp_dept_loc_vu FOR EACH USER;
E. CREATE SYNONYM EDL_VU FOR EACH USER ON emp_dept_loc_vu
F. CREATE PUBLIC SYNONYM EDL_VU ON emp_dept_loc_vu FOR ALL USERS;