单选题You just issued the following statement: ALTER TABLE SALES DROP COLUMN PROFIT. Which of the following choices identifies when the column will actually be removed from Oracle?（）A Immediately following statement execution B After the ALTER TABLE DROP UNU
题目
单选题
You just issued the following statement: ALTER TABLE SALES DROP COLUMN PROFIT. Which of the following choices identifies when the column will actually be removed from Oracle?（）
A
Immediately following statement execution
B
After the ALTER TABLE DROP UNUSED COLUMNS command is issued
C
After the ALTER TABLE SET UNUSED COLUMN command is issued
D
After the ALTER TABLE MODIFY command is issued