You are using flat files as the data source for one of your data warehousing applications. You plan to move the data from the flat file structures to an Oracle database to optimize the application performance. In your database you have clustered tables. While migrating the data， you want to have minimal impact on the database performance and optimize the data load operation. Which method would you use to load data into Oracle database？（）

A.The optimizer statistics are collected automatically.
B.Only the timed operating system （OS） statistics and plan execution statistics are collected.
C.The Oracle server dynamically generates the necessary statistics on tables as part of query optimization.
D.The snapshots for the Automatic Workload Repository （AWR） are not generated automatically. 
E.Snapshots cannot be collected manually by using DBMS_WORKLOAD_REPOSITORY PACKAGE.

A.Use the Database Resource Manager.
B.Set the limits in the profiles used by users.
C.Modify the SESSIONS initialization parameter.
D.Set the warning threshold for the Current Logons Count metric.

A.This clause is not valid for a temporary or undo tablespace.
B.If the tablespace is in the NOLOGGING mode，no operation on the tablespace will generate redo.
C.The tablespace will be in the NOLOGGING mode by default，if not specified while creating a tablespace.
D.The tablespace-level logging attribute can be overridden by logging specifications at the table，index， materialized view，materialized view log，and partition levels.