多选题Which statements are true regarding SecureFile LOBs?（）AThe amount of undo retained is user controlled.BSecureFile LOBs can be used only for nonpartitioned tables.CFragmentation is minimized by using variable-sized chunks dynamically.DSecureFile encrypt

第1题：

Which statements are true regarding the Query Result Cache？（） 

• A、 It can be set at the system， session， or table level.
• B、 It is used only across statements in the same session.
• C、 It can store the results from normal as well as flashback queries.
• D、 It can store the results of queries based on normal，temporary，and dictionary tables.

第2题：

Which two data types can be converted to LOBs using an ALTER TABLE… MODIFY command？（）

• A、RAW
• B、LONG
• C、VARCHAR
• D、LONG RAW

第3题：

Which two statements are true regarding the USING clause in table joins?（）

• A、It can be used to join a maximum of three tables 
• B、It can be used to restrict the number of columns used in a NATURAL join 
• C、It can be used to access data from tables through equijoins as well as nonequijoins 
• D、It can be used to join tables that have columns with the same name and compatible data types

第4题：

Which two statements are true regarding subqueries? （）

• A、A subquery can retrieve zero or more rows 
• B、Only two subqueries can be placed atone level 
• C、A subquery can be used only in SQL query statements 
• D、A subquery can appear on either side of a comparison operator 
• E、There is no limit on the number of subquery levels in the WHERE clause of a SELECT statement 

第5题：

Which two statements regarding a SQL profile are true？（）

• A、 It is built by Automatic Tuning Optimizer.
• B、 It cannot be stored persistently in the data dictionary.
• C、 It can be used by the query optimizer automatically.
• D、 It can be created manually by using the CREATE PROFILE command.

第6题：

Which statements are true regarding SecureFile LOBs？（） 

• A、 The amount of undo retained is user controlled.
• B、 SecureFile LOBs can be used only for nonpartitioned tables.
• C、 Fragmentation is minimized by using variable-sized chunks dynamically.
• D、 SecureFile encryption allows for random reads and writes of the encrypted data.
• E、 It automatically detects duplicate LOB data and conserves space by storing only one copy.

第7题：

Which statement describes the information returned by the DBMS_SPACE.SPACE_USAGE procedure for LOB space usage？（）

• A、 It returns space usage of only BasicFile LOB chunks.
• B、 It returns space usage of only SecureFile LOB chunks.
• C、 It returns both BasicFile and SecureFile LOB space usage for only nonpartitioned tables.
• D、 It returns both BasicFile and SecureFile LOB space usage for both partitioned and nonpartitioned tables.

第8题：

Which  statements are true regarding a tablespace（）

• A、It can span multiple databases.
• B、It can consist of multiple data files.
• C、It can contain blocks of different sizes.
• D、It can contain segments of different sizes.
• E、It can contain a part of a nonpartitioned segment

第9题：

Which two are true regarding direct-path exports？（）

• A、Direct-path export is typically faster.
• B、Direct-path export can be invoked interactively.
• C、Direct-path export is character set independent.
• D、Direct-path export bypasses the SQL-command processing layer.
• E、Direct-path export can be used to export rows containing LOBs and BFILEs.

第10题：

Which three statements are true regarding single-row functions？（）

• A、 They can accept only one argument.
• B、 They can be nested up to only two levels.
• C、 They can return multiple values of more than one data type.
• D、 They can be used in SELECT， WHERE， and ORDER BY clauses.  
• E、 They can modify the data type of the argument that is referenced.
• F、 They can accept a column name， expression， variable name， or a user-supplied constant as arguments.