[单项选择] Examine the structure of the EMPLOYEES table: Column name Data type Remarks EMPLOYEE_ID NUMBER NOT NULL, Primary Key LAST_NAME VARCNAR2(30) FIRST_NAME VARCNAR2(30) JOB_ID NUMBER SAL NUMBER MGR_ID NUMBER References EMPLOYEE_ID column DEPARTMENT_ID NUMBER You need to create an index called NAME_IDX on the first name and last name fields of the EMPLOYEES table. Which SQL statement would you use to perform this task? （）
A. CREATE INDEX NAME _IDX (first_name, last_name);
B. CREATE INDEX NAME _IDX (first_name, AND last_name)
C. CREATE INDEX NAME_IDX ON (First_name, last_name);
D. CREATE INDEX NAME_IDX ON employees (First_name, AND last_name);
E. CREATE INDEX NAME_IDX ON employees (First_name, last_name);
F. CREATE INDEX NAME_IDX FOR employees (First_name, last_name);

[单项选择] Examine the structure of the EMPLOYEES table: Column name Data type Remarks EMPLOYEE_ID NUMBER NOT NULL, Primary Key EMP_NAME VARCHAR2(30) JOB_ID VARCHAR2(20) NOT NULL SAL NUMBER MGR_ID NUMBER References EMPLOYEE_ID column DEPARTMENT_ID NUMBER Foreign key to DEPARTMENT_ID column of the DEPARTMENTS table You need to create a view called EMP_VU that allows the users to insert rows through the view. Which SQL statement, when used to create the EMP_VU view, allows the users to insert rows?（）
A. CREATE VIEW emp_vu AS SELECT employee_id, emp_name, department_id FROM employees WHERE mgr_id IN (102, 120);
B. CREATE VIEW emp_vu AS SELECT employee_id, emp_name, job_id, department_id FROM employees WHERE mgr_id IN (102, 120);
C. CREATE VIEW emp_vu AS SELECT department_id, SUM(sal) TOTALSAL FROM employees WHERE mgr_id IN (102, 120) GROUP BY department_id;
D. CREATE VIEW emp_vu AS SELECT employee_id, emp_name, job_id, DISTINCT department_id FROM employees;

[单项选择] Examine the structure if the EMPLOYEES table: Column name Data Type Remarks EMPLOYEE_ID NUMBER NOT NULL, Primary Key EMP_NAME VARCHAR2(30) JOB_ID VARCHAR2(20) NOT NULL SAL NUMBER MGR_ID NUMBER References EMPLOYEE_ID column DEPARTMENT_ID NUMBER Foreign key to DEPARTMENT_ID column of the DEPARTMENTS table You need to create a view called EMP_VU that allows the user to insert rows through the view. Which SQL statement, when used to create the EMP_VU view, allows the user to insert rows?（）
A. CREATE VIEW emp_Vu AS SELECT employee_id, emp_name, department_id FROM employees WHERE mgr_id IN (102, 120);
B. CREATE VIEW emp_Vu AS SELECT employee_id, emp_name, job_id department_id FROM employees WHERE mgr_id IN (102, 120);
C. CREATE VIEW emp_Vu AS SELECT department_id, SUM(sal) TOTALSAL FROM employees WHERE mgr_id IN (102, 120) GROUP BY department_ id;
D. CREATE VIEW emp_Vu AS SELECT employee_id, emp_name, job_id, DISTINCT department_id FROM employees;

[单项选择] Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER NOT NULL EMP_NAME VARCHAR2(30) JOB_ID VARCHAR2(20) SAL NUMBER MGR_ID NUMBER DEPARTMENT_ID NUMBER You want to create a SQL script file that contains an INSERT statement. When the script is run, the INSERT statement should insert a row with the specified values into the EMPLOYEES table. The INSERT statement should pass values to the table columns as specified below: EMPLOYEE_ID: Next value from the sequence EMP_ID_SEQEMP_NAME and JOB_ID: As specified by the user during run time, through substitution variables SAL: 2000 MGR_ID: No value DEPARTMENT_ID: Supplied by the user during run time through substitution variable. The INSERT statement should fail if the user supplies a value other than 20 or 50. Which INSERT statement meets the above requirements?（）
A. INSERT INTO employees VALUES (emp_id_seq.NEXTVAL, &ename','&jobid', 2000, NULL, &did);
B. INSERT INTO employees VALUES (emp_id_seq.NEXTVAL, '&ename', '&jobid', 2000, NULL, &did IN (20,50));
C. INSERT INTO (SELECT * FROM employees WHERE department_id IN (20,50)) VALUES (emp_id_seq.NEXTVAL, &ename','&jobid', 2000, NULL, &did);
D. INSERT INTO (SELECT * FROM employees WHERE department_id IN (20,50) WITH CHECK OPTION) VALUES (emp_id_seq.NEXTVAL, &ename','&jobid', 2000, NULL, &did);
E. INSERT INTO (SELECT * FROM employees WHERE (department_id = 20 AND department_id = 50) WITH CHECK OPTION ) VALUES (emp_id_seq.NEXTVAL, &ename','&jobid', 2000, NULL, &did);