Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER NOT NULL, Primary Key EMP_NAME VARCHAR2(30) JOB_ID NUMBER/ SAL NUMBER MGR_ID NUMBER References EMPLOYEE_ID column DEPARTMENT_ID NUMBER Foreign key to DEPARTMENT_ID column of the DEPARTMENTS

题目

Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER NOT NULL, Primary Key EMP_NAME VARCHAR2(30) JOB_ID NUMBER/ SAL NUMBER MGR_ID NUMBER References EMPLOYEE_ID column DEPARTMENT_ID NUMBER Foreign key to DEPARTMENT_ID column of the DEPARTMENTS table You created a sequence called EMP_ID_SEQ in orderto populate sequential values for the EMPLOYEE_ID column of the EMPLOYEES table. Which two statements regarding the EMP_ID_SEQ sequence are true? （）

A、You cannot use the EMP_ID_SEQ sequence to populate the JOB_ID column.
B、The EMP_ID_SEQ sequence is invalidated when you modify the EMPLOYEE_ID column.
C、The EMP_ID_SEQ sequence is not affected by modifications to the EMPLOYEES table.
D、Any other column of NUMBER data type in your schema can use the EMP_ID_SEQ sequence.
E、The EMP_ID_SEQ sequence is dropped automatically when you drop the EMPLOYEES table.
F、The EMP_ID_SEQ sequence is dropped automatically when you drop the EMPLOYEE_ID column.

参考答案和解析

正确答案:C,D

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相似问题和答案

第1题：

Examine the structure of the EMPLOYEES table:EMPLOYEE_ID NUMBER NOT NULLEMP_NAME VARCHAR2(30)JOB_ID VARCHAR2(20) DEFAULT ‘SA_REP‘SAL NUMBERCOMM_PCT NUMBERMGR_ID NUMBERDEPARTMENT_ID NUMBERYou need to update the records of employees 103 and 115. The UPDATE statement you specify should update the rows with the values specified below:JOB_ID: Default value specified for this column definition.SAL: Maximum salary earned for the job ID SA_REP.COMM_PCT: Default value specified for this commission percentage column, if any. If no default value is specified for the column, the value should be NULL. DEPARTMENT_ID: Supplied by the user during run time through substitution variable.Which UPDATE statement meets the requirements?（）

A. UPDATE employees SET job_id = DEFAULT AND Sal = (SELECT MAX(sal) FROM employees WHERE job_id = ‘SA_REP‘) AND comm_pct = DEFAULT AND department_id = &did WHERE employee _id IN (103,115);

B. UPDATE employees SET job_id = DEFAULT AND Sal = MAX(sal) AND comm_pct = DEFAULT OR NULL AND department_id = &did WHERE employee_id IN (103,115) AND job _ id = ‘SA_ REP‘;

C. UPDATE employees SET job_id = DEFAULT, Sal = (SELECT MAX(sal) FROM employees WHERE job_id = ‘SA_REP‘), comm_pct = DEFAULT, department_id = &did WHERE employee_id IN (103,115);

D. UPDATE employees SET job_id = DEFAULT, Sal = MAX(sal), comm_pct = DEFAULT, department_id = &did WHERE employee_id IN (103,115) AND job _ id = ‘SA_ REP‘;

E. UPDATE employees SET job_id = DEFAULT, Sal = (SELECT MAX(sal) FROM employees WHERE job_id = ‘SA_REP‘) comm_pct = DEFAULT OR NULL, department_id = &did WHERE employee_id IN (103,115);

参考答案：C

第2题：

Click the Exhibit button and examine the data in the EMPLOYEES table.On the EMPLOYEES table, EMPLOYEE_ID is the primary key. MGR_ID is the ID of managers and refers to the EMPLOYEE_ID. The JOB_ID column is a NOT NULL column.Evaluate this DELETE statement:DELETE employee_id, salary, job_idFROM employeesWHERE dept_id = 90;Why does the DELETE statement fail when you execute it?（）

A.There is no row with dept_id 90 in the EMPLOYEES table.

B.You cannot delete the JOB_ID column because it is a NOT NULL column.

C.You cannot specify column names in the DELETE clause of the DELETE statement.

D.You cannot delete the EMPLOYEE_ID column because it is the primary key of the table.

参考答案：C

第3题：

Which SQL statement defines the FOREIGN KEY constraint on the DEPTNO column of the EMP table? ()

A. CREATE TABLE EMP (empno NUMBER(4), ename VARCNAR2(35), deptno NUMBER(7,2) NOT NULL CONSTRAINT emp_deptno_fk FOREIGN KEY deptno REFERENCES dept deptno);

B. CREATE TABLE EMP (empno NUMBER(4), ename VARCNAR2(35), deptno NUMBER(7,2) CONSTRAINT emp_deptno_fk REFERENCES dept (deptno));

C. CREATE TABLE EMP (empno NUMBER(4) ename VARCHAR2(35), deptno NUMBER(7,2) NOT NULL, CONSTRAINT emp_deptno_fk REFERENCES dept (deptno) FOREIGN KEY (deptno));

D. CREATE TABLE EMP (empno NUMBER(4), ename VARCNAR2(35), deptno NUMBER(7,2) FOREIGN KEY CONSTRAINT emp deptno fk REFERENCES dept (deptno));

参考答案：B

第4题：

You need to design a student registration database that contains several tables storing academic information. The STUDENTS table stores information about a student. The STUDENT_GRADES table stores information about the student's grades. Both of the tables have a column named STUDENT_ID. The STUDENT_ID column in the STUDENTS table is a primary key. You need to create a foreign key on the STUDENT_ID column of the STUDENT_GRADES table that points to the STUDENT_ID column of the STUDENTS table. Which statement creates the foreign key?（）

A、CREATE TABLE student_grades (student_id NUMBER(12),semester_end DATE, gpa NUMBER(4,3), CONSTRAINT student_id_fk REFERENCES (student_id) FOREIGN KEY student (student_id));
B、CREATE TABLE student_grades(student_id NUMBER(12),semester_end DATE, gpa NUMBER(4,3), student_id_fk FOREIGN KEY (student_id) REFERENCES students (student_id));
C、CREATE TABLE student_grades(student_id NUMBER(12),semester_end DATE, gpa NUMBER(4,3), CONSTRAINT FOREIGN KEY (student_id) REFERENCES student (student_id));
D、CREATE TABLE student_grades(student_id NUMBER(12),semester_end DATE, gpa NUMBER(4,3), CONSTRAINT student_id_fk FOREIGN KEY (student_id) REFERENCES students (student_id));

正确答案:D

第5题：

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;

正确答案:B

第6题：

Examine the data in the EMPLOYEES and DEPARTMENTS tables:

EMPLOYEES

EMP_NAME DEPT_ID MGR_ID JOB_ID SALARY

EMPLOYEE_ID

101 Smith 20 120 SA_REP 4000

102 Martin 10 105 CLERK 2500

103 Chris 20 120 IT_ADMIN 4200

104 John 30 108 HR_CLERK 2500

105 Diana 30 108 IT_ADMIN 5000

106 Smith 40 110 AD_ASST 3000

108 Jennifer 30 110 HR_DIR 6500

110 Bob 40 EX_DIR 8000

120 Ravi 20 110 SA*DIR 6500

DEPARTMENTS

DEPARTMENT_ID DEPARTMENT_NAME

10 Admin

20 Education

30 IT

40 Human Resources

Also examine the SQL statements that create the EMPLOYEES and DEPARTMENTS tables:

CREATE TABLE departments

(department_id NUMBER PRIMARY KEY,

department _ name VARCHAR2(30));

CREATE TABLE employees

(EMPLOYEE_ID NUMBER PRIMARY KEY,

EMP_NAME VARCHAR2(20),

DEPT_ID NUMBER REFERENCES

departments(department_id),

MGR_ID NUMBER REFERENCES

employees(employee id),

MGR_ID NUMBER REFERENCES

employees(employee id),

JOB_ID VARCHAR2(15).

SALARY NUMBER);

ON the EMPLOYEES,

On the EMPLOYEES table, EMPLOYEE_ID is the primary key.

MGR_ID is the ID of managers and refers to the EMPLOYEE_ID. DEPT_ID is foreign key to DEPARTMENT_ID column of the DEPARTMENTS table. On the DEPARTMENTS table, DEPARTMENT_ID is the primary key.

Examine this DELETE statement:

DELETE

FROM departments

WHERE department id = 40;

What happens when you execute the DELETE statement?（）

参考答案：B

第7题：

Examine the structure of the EMPLOYEES and DEPARTMENTS tables: EMPLOYEESColumn name Data type Remarks EMPLOYEE_ID NUMBER NOT NULL, Primary Key EMP_NAME VARCHAR2 (30) JOB_ID VARCHAR2 (20) SALARY NUMBER MGR_ID NUMBER References EMPLOYEE_ID COLUMN DEPARTMENT ID NUMBER Foreign key to DEPARTMENT ID column of the DEPARTMENTS table DEPARTMENTSColumn name Data type Remarks DEPARTMENT_ID NUMBER NOT NULL, Primary Key DEPARTMENT_NAME VARCHAR2(30) MGR_ID NUMBER References MGR_ID column of the EMPLOYEES table Evaluate this SQL statement: SELECT employee_id, e.department_id, department_name, salary FROM employees e, departments d WHERE e. department_id = d.department_id; Which SQL statement is equivalent to the above SQL statement? （）

A、SELECT employee_id, department_id, department_name, salary FROM employees WHERE department_id IN (SELECT department_id FROM departments);
B、SELECT employee_id, department_id, department_name, salary FROM employees NATURAL JOIN departments;
C、SELECT employee_id, d.department_id, department_name, salary FROM employees e JOIN departments d ON e.department _ id = d. department_id;
D、SELECT employee_id, department_id, department_name, Salary FROM employees JOIN departments USING (e.department_id, d.department_id);

正确答案:C

第8题：

Examine the data in the EMPLOYEES table.On the EMPLOYEES table, EMPLOYEE_ID is the primary key. MGR_ID is the ID of managers and refers to the EMPLOYEE_ID. The JOB_ID column is a NOT NULL column.Evaluate this DELETE statement:Why does the DELETE statement fail when you execute it?（）

A. There is no row with dept_id 90 in the EMPLOYEES table.

B. You cannot delete the JOB_ID column because it is a NOT NULL column.

C. You cannot specify column names in the DELETE clause of the DELETE statement.

D. You cannot delete the EMPLOYEE_ID column because it is the primary key of the table.

参考答案：C

第9题：

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?（）

A、ALTER VIEW EMP_dept_vu (ADD manger_id NUMBER);
B、MODIFY VIEW EMP_dept_vu (ADD manger_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.

正确答案:E

第10题：

Which SQL statement defines the FOREIGN KEY constraint on the DEPTNO column of the EMP table?（）

A、CREATE TABLE EMP (empno NUMBER(4), ename VARCNAR2(35), deptno NUMBER(7,2) NOT NULL CONSTRAINT emp_deptno_fk FOREIGN KEY deptno REFERENCES dept deptno);
B、CREATE TABLE EMP (empno NUMBER(4), ename VARCNAR2(35), deptno NUMBER(7,2) CONSTRAINT emp_deptno_fk REFERENCES dept (deptno));
C、CREATE TABLE EMP (empno NUMBER(4) ename VARCHAR2(35), deptno NUMBER(7,2) NOT NULL, CONSTRAINT emp_deptno_fk REFERENCES dept (deptno) FOREIGN KEY (deptno));
D、CREATE TABLE EMP (empno NUMBER(4), ename VARCNAR2(35), deptno NUMBER(7,2) FOREIGN KEY CONSTRAINT emp deptno fk REFERENCES dept (deptno));

正确答案:B

Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER NOT NULL, Primary Key EMP_NAME VARCHAR2(30) JOB_ID NUMBER/ SAL NUMBER MGR_ID NUMBER References EMPLOYEE_ID column DEPARTMENT_ID NUMBER Foreign key to DEPARTMENT_ID column of the DEPARTMENTS

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