出自:Oracle认证
Review the definition of the phone_list view. CHEATE OR REPLACE ALGORITHM=MERGE DEFINER= 'root'@localhost' SQL SECURITY DEFINER VIEW 'phone_list' AS SELECT e . id as id 'e . first_name AS 'first_name' 'e . last_name AS 'last_name' 'coalesce ( ph1.phone_no, ' – ') AS 'office_no' 'coalesce (ph2 .phone_no, ' – ') AS 'cell_no' FROM employees e LEFT JOIN employee_phone ph1 ON ph1.emp_id = e.id AND ph1.type = 'office' LEFT JOIN employee_phone ph2 ON ph2 .emp_id = e.id AND ph2 .type = 'mobile' The tables employees and employee_phone are InnoDB tables; all columns are used in this view. The contents of the phone_list view are as follows: Mysql> select * from phone_list; 1 row in set (0.00 sec) Which method can you use to change the cell_no value to '555-8888' for John Doe?（）
A:INSERT INTO employee_phone (emp_id, phone_no, type) VALUES (1, '555-8888','mobile')
B:UPDATE phone_list SET cell_name '555-8888' WHERE first_name= 'John' and last_name= 'Doe'
C:DELETE FROM phone_list WHERE first_name= 'John' and last_name= 'Doe'; INSERT INTO phone_list (first_name, last_name, office_no, cell_no) VALUES ('John' , 'Doe' , 'x1234' , '555-8888)
D:UPDATE employee_phone SET phone_no= '555-8888' where emp_id=1
Examine the structure of the EMPLOYEES and DEPARTMENTS tables: EMPLOYEES EMPLOYEE_ID NUMBER DEPARTMENT_ID NUMBER MANAGER_ID NUMBER LAST_NAME VARCHAR2(25) DEPARTMENTS DEPARTMENT_ID NUMBER MANAGER_ID NUMBER DEPARTMENT_NAME VARCHAR2(35) LOCATION_ID NUMBER You want to create a report displaying employee last names, department names, and locations. Which query should you use?（）
A:SELECT e.last_name, d. department_name, d.location_id FROM employees e NATURAL JOIN departments D USING department_id ;
B:SELECT last_name, department_name, location_id FROM employees NATURAL JOIN departments WHERE e.department_id =d.department_id;
C:SELECT e.last_name, d.department_name, d.location_id FROM employees e NATURAL JOIN departments d;
D:SELECT e.last_name, d.department_name, d.location_id FROM employees e JOIN departments d USING (department_id );
Examine the description of the EMPLOYEES table: EMP_ID NUMBER(4) NOT NULL LAST_NAME VARCHAR2(30) NOT NULL FIRST_NAME VARCHAR2(30) DEPT_ID NUMBER(2) JOB_CAT VARCHARD2(30) SALARY NUMBER(8,2) Which statement shows the maximum salary paid in each job category of each department? （）
A:SELECT dept_id, job_cat, MAX(salary) FROM employees WHERE salary > MAX (salary);
B:SELECT dept_id, job_cat, MAX(salary) FROM employees GROUP BY dept_id,job_cat;
C:SELECT dept_id, job_cat, MAX(salary) FROM employees;
D:SELECT dept_id, job_cat, MAX(salary) FROM employees GROUP BY dept_id;
E:SELECT dept_id, job_cat, MAX(salary) FROM employees GROUP BY dept _ id job _ cat salary;
Which statement is true？（）
What three changes allow the class to be used with generics and avoid an unchecked warning？（）
What is the result?（）
Which two， inserted at line 11， will allow the code to compile？（）