You own a table called EMPLOYEES with this table structure: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE What happens when you execute this DELETE statement? DELETE employees;（）A、You get an error because of

题目

You own a table called EMPLOYEES with this table structure: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE What happens when you execute this DELETE statement? DELETE employees;（）

  • A、You get an error because of a primary key violation.
  • B、The data and structure of the EMPLOYEES table are deleted.
  • C、The data in the EMPLOYEES table is deleted but not the structure.
  • D、You get an error because the statement is not syntactically correct.
相似考题

1.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.

2.Examine the data in the EMPLOYEES and DEPARTMENTS tables:EMPLOYEESEMP_NAME DEPT_ID MGR_ID JOB_ID SALARYEMPLOYEE_ID101 Smith 20 120 SA_REP 4000102 Martin 10 105 CLERK 2500103 Chris 20 120 IT_ADMIN 4200104 John 30 108 HR_CLERK 2500105 Diana 30 108 IT_ADMIN 5000106 Smith 40 110 AD_ASST 3000108 Jennifer 30 110 HR_DIR 6500110 Bob 40 EX_DIR 8000120 Ravi 20 110 SA*DIR 6500DEPARTMENTSDEPARTMENT_ID DEPARTMENT_NAME10 Admin20 Education30 IT40 Human ResourcesAlso 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 REFERENCESdepartments(department_id),MGR_ID NUMBER REFERENCESemployees(employee id),MGR_ID NUMBER REFERENCESemployees(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:DELETEFROM departmentsWHERE department id = 40;What happens when you execute the DELETE statement?（）

3.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.

4.Examine the data in the EMPLOYEES and DEPARTMENTS tables:Also examine the SQL statements that create the EMPLOYEES and DEPARTMENTS tables: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:What happens when you execute the DELETE statement?（）A. Only the row with department ID 40 is deleted in the DEPARTMENTS table.B. The statement fails because there are child records in the EMPLOYEES table with department ID 40.C. The row with department ID 40 is deleted in the DEPARTMENTS table. Also the rows with employee IDs 110 and 106 are deleted from the EMPLOYEES table.D. The row with department ID 40 is deleted in the DEPARTMENTS table. Also the rows with employee IDs 106 and 110 and the employees working under employee 110 are deleted from the EMPLOYEES table.E. The row with department ID 40 is deleted in the DEPARTMENTS table. Also all the rows in the EMPLOYEES table are deleted.F. The statement fails because there are no columns specifies in the DELETE clause of the DELETE statement.

更多“You own a table called EMPLOYEES with this table structure: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE What happens when you execute this DELETE statement? DELETE employees;（）A、You get an error because of ”相关问题

  • 第1题：

    Examine the structure of the EMPLOYEES and NEW_EMPLOYEES tables: EMPLOYEES EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2 (25) LAST_NAME VARCHAR2 (25) HIRE_DATE DATE NEW EMPLOYEES EMPLOYEE_ID NUMBER Primary Key NAME VARCHAR2 (60) Which DELETE statement is valid? （）

    • A、DELETE FROM employees WHERE employee_id = (SELECT employee_id FROM employees);
    • B、DELETE * FROM employees WHERE employee_id = (SELECT employee_id FROM new_ employees);
    • C、DELETE FROM employees WHERE employee_id IN (SELECT employee_id FROM new_employees WHERE name = ('Carrey')'
    • D、DELETE * FROM employees WHERE employee_id IN (SELECT employee_id FROM new_employees WHERE last_ name = ('Carrey')'

    正确答案:C

  • 第2题：

    Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE Which INSERT statement is valid?（）

    • A、INSERT INTO employees (employee_id, first_name, last_name, hire_date) VALUES (1000, 'John', 'smith','01/01/01);
    • B、INSERT INTO employees(employee_id, first_name, last_name, hire_date) VALUES (1000, 'John', 'smith','01 january 01');
    • C、INSERT INTO employees(employee_id, first_name, last_name, Hire_date) VALUES (1000, 'John', 'smith', To_ date ('01/01/01));
    • D、INSERT INTO employees(employee_id, first_name, last_name, hire_date) VALUES (1000, 'John', 'smith','01-Jan-01');

    正确答案:A

  • 第3题：

    Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE You issue these statements: CREATE table new_emp ( employee_id NUMBER, name VARCHAR2(30)); INSERT INTO new_emp SELECT employee_id , last_name from employees; Savepoint s1; UPDATE new_emp set name = UPPER(name); Savepoint s2; Delete from new_emp; Rollback to s2; Delete from new_emp where employee_id =180; UPDATE new_emp set name = 'James'; Rollback to s2; UPDATE new_emp set name = 'James' WHERE employee_id =180; Rollback; At the end of this transaction, what is true?（）

    • A、You have no rows in the table.
    • B、You have an employee with the name of James.
    • C、You cannot roll back to the same savepoint more than once.
    • D、Your last update fails to update any rows because employee ID 180 was already deleted.

    正确答案:A

  • 第4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?（）

    • A、Only the row with department ID 40 is deleted in the DEPARTMENTS table.
    • B、The statement fails because there are child records in the EMPLOYEES table with department ID 40.
    • C、The row with department ID 40 is deleted in the DEPARTMENTS table. Also the rows with employee IDs 110 and 106 are deleted from the EMPLOYEES table.
    • D、The row with department ID 40 is deleted in the DEPARTMENTS table. Also the rows with employee IDs 106 and 110 and the employees working under employee 110 are deleted from the EMPLOYEES table.
    • E、The row with department ID 40 is deleted in the DEPARTMENTS table. Also all the rows in the EMPLOYEES table are deleted.
    • F、The statement fails because there are no columns specifies in the DELETE clause of the DELETE statement.

    正确答案:B

  • 第5题：

    Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2 (25) LAST_NAME VARCHAR2 (25) HIRE_DATE DATE Which UPDATE statement is valid? （）

    • A、UPDATE employees SET first_name = 'John' SET last_name = 'Smith' WHERE employee_id = 180;
    • B、UPDATE employees SET first_name = 'John', SET last_name = 'Smoth' WHERE employee_id = 180;
    • C、UPDATE employee SET first_name = 'John' AND last_name = 'Smith' WHERE employee_id = 180;
    • D、UPDATE employee SET first_name = 'John', last_name = 'Smith' WHERE employee_id = 180;

    正确答案:D

  • 第6题：

    Examine the structure of the EMPLOYEES and NEW_EMPLOYEES tables: EMPLOYEES EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE NEW_EMPLOYEES EMPLOYEE_ID NUMBER Primary Key NAME VARCHAR2(60) Which DELETE statement is valid?（）

    • A、DELETE FROM employees WHERE employee_id = (SELECT employee_id FROM employees);
    • B、DELETE * FROM employees WHERE employee_id = (SELECT employee_id FROM new_employees);
    • C、DELETE FROM employees WHERE employee_id IN (SELECT employee_id FROM new_employees WHERE name ='Carrey');
    • D、DELETE * FROM employees WHERE employee_id IN (SELECT employee_id FROM new_employees WHERE last_name ='Carrey');

    正确答案:C

  • 第7题：

    单选题
    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.


    正确答案： B
    解析： 暂无解析

  • 第8题：

    单选题
    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?（）
    A

    Only the row with department ID 40 is deleted in the DEPARTMENTS table.

    B

    The statement fails because there are child records in the EMPLOYEES table with department ID 40.

    C

    The row with department ID 40 is deleted in the DEPARTMENTS table. Also the rows with employee IDs 110 and 106 are deleted from the EMPLOYEES table.

    D

    The row with department ID 40 is deleted in the DEPARTMENTS table. Also the rows with employee IDs 106 and 110 and the employees working under employee 110 are deleted from the EMPLOYEES table.

    E

    The row with department ID 40 is deleted in the DEPARTMENTS table. Also all the rows in the EMPLOYEES table are deleted.

    F

    The statement fails because there are no columns specifies in the DELETE clause of the DELETE statement.


    正确答案： C
    解析： 暂无解析

  • 第9题：

    单选题
    Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE You issue these statements: CREATE table new_emp ( employee_id NUMBER, name VARCHAR2(30)); INSERT INTO new_emp SELECT employee_id , last_name from employees; Savepoint s1; UPDATE new_emp set name = UPPER(name); Savepoint s2; Delete from new_emp; Rollback to s2; Delete from new_emp where employee_id =180; UPDATE new_emp set name = 'James'; Rollback to s2; UPDATE new_emp set name = 'James' WHERE employee_id =180; Rollback; At the end of this transaction, what is true?（）
    A

    You have no rows in the table.

    B

    You have an employee with the name of James.

    C

    You cannot roll back to the same savepoint more than once.

    D

    Your last update fails to update any rows because employee ID 180 was already deleted.


    正确答案： C
    解析： 暂无解析

  • 第10题：

    单选题
    Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2 (25) LAST_NAME VARCHAR2 (25) HIRE_DATE DATE Which UPDATE statement is valid? （）
    A

    UPDATE employees SET first_name = 'John' SET last_name = 'Smith' WHERE employee_id = 180;

    B

    UPDATE employees SET first_name = 'John', SET last_name = 'Smoth' WHERE employee_id = 180;

    C

    UPDATE employee SET first_name = 'John' AND last_name = 'Smith' WHERE employee_id = 180;

    D

    UPDATE employee SET first_name = 'John', last_name = 'Smith' WHERE employee_id = 180;


    正确答案： D
    解析： 暂无解析

  • 第11题：

    单选题
    Examine the structure of the EMPLOYEES and NEW_EMPLOYEES tables: EMPLOYEES EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2 (25) LAST_NAME VARCHAR2 (25) HIRE_DATE DATE NEW EMPLOYEES EMPLOYEE_ID NUMBER Primary Key NAME VARCHAR2 (60) Which DELETE statement is valid? （）
    A

    DELETE FROM employees WHERE employee_id = (SELECT employee_id FROM employees);

    B

    DELETE * FROM employees WHERE employee_id = (SELECT employee_id FROM new_ employees);

    C

    DELETE FROM employees WHERE employee_id IN (SELECT employee_id FROM new_employees WHERE name = ('Carrey')'

    D

    DELETE * FROM employees WHERE employee_id IN (SELECT employee_id FROM new_employees WHERE last_ name = ('Carrey')'


    正确答案： A
    解析： 暂无解析

  • 第12题：

    多选题
    Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) Which three statements inserts a row into the table? （）
    A

    INSERT INTO employees VALUES (NULL, 'JOHN','Smith');

    B

    INSERT INTO employees( first_name, last_name) VALUES ('JOHN','Smith');

    C

    INSERT INTO employees VALUES ('1000','JOHN','NULL');

    D

    INSERT INTO employees(first_name,last_name, employee_id) VALUES ('1000, 'john','Smith');

    E

    INSERT INTO employees (employee_id) VALUES (1000);

    F

    INSERT INTO employees (employee_id, first_name, last_name) VALUES ( 1000, 'john',);


    正确答案： E,D
    解析： 暂无解析

  • 第13题：

    Examine the data in the EMPLOYEES table. 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 EK_DIR 8000 120 Revi 20 110 SA_DIR 6500 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_id FROM employees WHERE 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.

    正确答案:C

  • 第14题：

    Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) Which three statements inserts a row into the table? （）

    • A、INSERT INTO employees VALUES (NULL, 'JOHN','Smith');
    • B、INSERT INTO employees( first_name, last_name) VALUES ('JOHN','Smith');
    • C、INSERT INTO employees VALUES ('1000','JOHN','NULL');
    • D、INSERT INTO employees(first_name,last_name, employee_id) VALUES ('1000, 'john','Smith');
    • E、INSERT INTO employees (employee_id) VALUES (1000);
    • F、INSERT INTO employees (employee_id, first_name, last_name) VALUES ( 1000, 'john',");

    正确答案:C,E,F

  • 第15题：

    Examine the structure of the EMPLOYEES and NEW_EMPLOYEES tables: EMPLOYEES EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE NEW_EMPLOYEES EMPLOYEE_ID NUMBER Primary Key NAME VARCHAR2 (60) Which DELETE statement is valid?（）

    • A、DELETE FROM employees WHERE employee_id = (SELECT employee_id FROM employees);
    • B、DELETE * FROM employees WHERE employee_id = (SELECT employee_id FROM new_ employees);
    • C、DELETE FROM employees WHERE employee_id IN (SELECT employee_id FROM new_employees WHERE name = 'carrey');
    • D、DELETE * FROM employees WHERE employee_id IN (SELECT employee_id FROM new_employees WHERE name = 'carrey');

    正确答案:C

  • 第16题：

    Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE Which UPDATE statement is valid?（）

    • A、UPDATE employees SET first_name = 'John' SET last_name ='Smith' WHERE employee_id = 180;
    • B、UPDATE employees SET first_name = 'John', SET last_name ='Smith' WHERE employee_id = 180;
    • C、UPDATE employees SET first_name = 'John' AND last_name ='Smith' WHERE employee_id = 180;
    • D、UPDATE employees SET first_name = 'John', last_name ='Smith' WHERE employee_id = 180;

    正确答案:D

  • 第17题：

    Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE You issue these statements: CREATE table new_emp ( employe_id NUMBER, name VARCGAR2(30)); INSERT INTO new_emp SELECT employee_id, last_name from employees; Savepoint s1; UPDATE new_emp set name = UPPER(name); Savepoint s2; Delete from new_emp; Rollback to s2; Delete from new_emp where employee_id=180; UPDATE new_emp set name = 'James'; Rollback to s2; UPDATE new_emp sey name = 'James' Where employee_id=180; Rollback; At the end of this transaction, what is true?（）

    • A、You have no rows in the table.
    • B、You have an employee with the name of James.
    • C、You cannot roll back to the same savepoint more than once.
    • D、Your last update fails to update any rows because employee ID 180 was already deleted.

    正确答案:A

  • 第18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.

    正确答案:D

  • 第19题：

    单选题
    You own a table called EMPLOYEES with this table structure: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE What happens when you execute this DELETE statement? DELETE employees; （）
    A

    You get an error because of a primary key violation.

    B

    The data and structure of the EMPLOYEES table are deleted.

    C

    The data in the EMPLOYEES table is deleted but not the structure.

    D

    You get an error because the statement is not syntactically correct.


    正确答案： D
    解析： 暂无解析

  • 第20题：

    单选题
    Examine the structure of the EMPLOYEES and NEW_EMPLOYEES tables: EMPLOYEES EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE NEW_EMPLOYEES EMPLOYEE_ID NUMBER Primary Key NAME VARCHAR2 (60) Which DELETE statement is valid?（）
    A

    DELETE FROM employees WHERE employee_id = (SELECT employee_id FROM employees);

    B

    DELETE * FROM employees WHERE employee_id = (SELECT employee_id FROM new_ employees);

    C

    DELETE FROM employees WHERE employee_id IN (SELECT employee_id FROM new_employees WHERE name = 'carrey');

    D

    DELETE * FROM employees WHERE employee_id IN (SELECT employee_id FROM new_employees WHERE name = 'carrey');


    正确答案： C
    解析： 暂无解析

  • 第21题：

    单选题
    You own a table called EMPLOYEES with this table structure: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE What happens when you execute this DELETE statement? DELETE employees;（）
    A

    You get an error because of a primary key violation.

    B

    The data and structure of the EMPLOYEES table are deleted.

    C

    The data in the EMPLOYEES table is deleted but not the structure.

    D

    You get an error because the statement is not syntactically correct.


    正确答案： D
    解析： 暂无解析

  • 第22题：

    多选题
    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 order to 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.


    正确答案： C,B
    解析： 暂无解析

  • 第23题：

    单选题
    Examine the structure of the EMPLOYEES and NEW_EMPLOYEES tables: EMPLOYEES EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE NEW_EMPLOYEES EMPLOYEE_ID NUMBER Primary Key NAME VARCHAR2(60) Which DELETE statement is valid?（）
    A

    DELETE FROM employees WHERE employee_id = (SELECT employee_id FROM employees);

    B

    DELETE * FROM employees WHERE employee_id = (SELECT employee_id FROM new_employees);

    C

    DELETE FROM employees WHERE employee_id IN (SELECT employee_id FROM new_employees WHERE name ='Carrey');

    D

    DELETE * FROM employees WHERE employee_id IN (SELECT employee_id FROM new_employees WHERE last_name ='Carrey');


    正确答案： B
    解析： 暂无解析

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