167. Evaluate the following DELETE statement:
DELETE FROM sales;
There are no other uncommitted transactions on the SALES table.
Which statement is true about the DELETE statement?
A. It would not remove the rows if the table has a primary key.
B. It removes all the rows as well as the structure of the table.
C. It removes all the rows in the table and deleted rows can be rolled back.
D. It removes all the rows in the table and deleted rows cannot be rolled back.
Answer: C
答案解析：
参考：http://blog.csdn.net/rlhua/article/details/12885143
A，如果表中有主键则不能移除行，错误，有主键是可以删除的
B，移除表中所有行及表结构，错误，表结构是保留的
C，移除表中所有行，并且删除的行可以回滚，正确，删除的数据保留在undo段，可以回滚。
D，移除表中所有行，并且删除的行不可以回滚，错误，删除的行是可以回滚的。