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