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.
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