为自己加油

Examine these commands
[oracle@host01 ~]$ sqlplus u1/oracle
SQL > SELECT * FROM emp;
ENO ENAME DN
---------------------------------
1 Alan 2
2 Ben 2
SEL > exit
[oracle@host01 ~] cat emp.dat
1,Alan,2
3,Curl,4
4,Bob,4
[oracle@host01 ~] sqlldr u1/oracle TABLE=emp
Which two statements are true about the sqlldr execution?

A.It overwrites the data for Alan and adds data for Curl and Bob
B.It generates a sql script that it uses to load data from EMP. DAT to EMP
C.It overwrites all data in EMP with data from EMP. DAT.
D.It generates a log that contains control file entries, which can be used with normal SQL*Loader
Operations
E.It appends data from EMP. DAT to EMP.