單項(xiàng)選擇題

The EMPLOYEES table has these columns:
LAST_NAME VARCHAR2(35)
SALARY NUMBER(8,2)
HIRE_DATE DATE
Management wants to add a default value to the SALARY column. You plan to alter the table by using this SQL statement:
ALTER TABLE EMPLOYEES
MODIFY (SALARY DEFAULT 5000);
Which 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 to 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.

你可能感興趣的試題

單項(xiàng)選擇題

Click the Exhibit button to examine the data of the EMPLOYEES table.
Which statement lists the ID, name, and salary of the employee, and the ID and name of the employee's manager, for all the employees who have a manager and earn more than 4000?（）

A.SELECT employee_id "Emp_id", emp_name "Employee", salary, employee_id "Mgr_id", emp_name "Manager" FROM employees WHERE salary > 4000;
B.SELECT e.employee_id "Emp_id", e.emp_name "Employee", e.salary, m.employee_id "Mgr_id", m.emp_name "Manager" FROM employees e JOIN employees m WHERE e.mgr_id = m.mgr_id AND e.salary > 4000;
C.SELECT e.employee_id "Emp_id", e.emp_name "Employee", e.salary, m.employee_id "Mgr_id", m.emp_name "Manager" FROM employees e JOIN employees m ON (e.mgr_id = m.employee_id) AND e.salary > 4000;
D.SELECT e.employee_id "Emp_id", e.emp_name "Employee", e.salary, m.mgr_id "Mgr_id", m.emp_name "Manager" FROM employees e SELF JOIN employees m WHERE e.mgr_id = m.employee_id AND e.salary > 4000;
E.SELECT e.employee_id "Emp_id", e.emp_name "Employee", e.salary, m.mgr_id "Mgr_id" m.emp_name "Manager" FROM employees e JOIN employees m USING (e.employee_id = m.employee_id) AND e.salary > 4000;

單項(xiàng)選擇題

A subquery can be used to（）.

A.create groups of data
B.sort data in a specific order
C.convert data to a different format
D.retrieve data based on an unknown condition

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你可能感興趣的試題

Click the Exhibit button to examine the data of the EMPLOYEES table. Which statement lists the ID, name, and salary of the employee, and the ID and name of the employee's manager, for all the employees who have a manager and earn more than 4000?（）

A subquery can be used to（）.

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Click the Exhibit button to examine the data of the EMPLOYEES table.
Which statement lists the ID, name, and salary of the employee, and the ID and name of the employee's manager, for all the employees who have a manager and earn more than 4000?（）