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The EMPLOYEES table has these columns:
LAST NAMEVARCHAR2(35)
SALARYNUMBER(8,2)
HIRE_DATEDATE
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);
What 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 at 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.
Correct Answer: B
Explanation/Reference:
Explanation:
A change to the DEFAULT value affects only subsequent insertions to the table. Existing rows will not be affected.
Incorrect Answers
A:Column definitions can be altered to add DEFAULT values.
C:Column definitions can be altered to add DEFAULT values. It works for columns with a NUMBER data type also.
D:A change to the DEFAULT value affects only subsequent insertions to the table. Existing rows will not be affected.
OCP Introduction to Oracle 9i: SQL Exam Guide, Jason Couchman, p. 219-224
Chapter 5: Creating Oracle Database Objects
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