A.The extents in the undo tablespace retain data until the next full database backup.
B.The extents containing committed undo in the undo tablespace are not overwritten for at least 15minutes.
C.The extents containing committed data in the undo tablespace are not overwritten until the instance isshut down.
D.The extents containing committed undo in the undo tablespace are transferred to Flash Recovery Areabefore being overwritten.

A.The DML commands will fail.
B.The undo data generated by the DML is stored in one of the two other undo tablespaces.
C.The undo data generated by the DML will overwrite the extents that contain committed undo data. 
D.The undo data generated by the DML is stored in the SYSTEM undo segment of the SYSTEM

A.The database can have more than one undo tablespace.
B.The UNDO_TABLESPACE parameter is valid in both automatic andmanualundo management.
C.Undo segments automatically grow and shrink as needed， acting as circular storage buffer for their assigned transactions.
D.An undotablespaceis automatically created if the UNDO_TABLESPACEparameter is not set and the UNDO_MANAGEMENT parameter is set to AUTO during the database instance start up.

A.committing a transaction
B.flashing back a transaction
C.recovering a failed transaction
D.running a read-consistent query
E.changing a tablespace status from READ ONLY to READ WRITE

A.An extent cannot spread across data files.
B.A segment cannot spread across data files.
C.A data file can belong to only one tablespace.
D.A data file can have only one segment created in it.
E.A data block can spread across multiple data files as it can consist of multiple operating system （OS） blocks.

A.2， 5， 1， 4， 3
B.1， 2， 3， 4， 5
C.5， 2， 1， 3， 4
D.2， 1， 5， 4， 3

A.external table
B.partitioned table
C.partitioned index
D.nonclustered table
E.global temporary table

A.Each segment contains one or more extents.
B.Multiple tablespaces can share a single data file.
C.A data block is the smallest unit of input/output （I/O） in data files.
D.It is possible to have tablespaces of different block sizes in a database.
E.Each data block in the database always corresponds to one operating system block.

A.System monitor （SMON）
B.Process monitor （PMON）
C.Memory manager process （MMAN）
D.Manageability Monitor process （MMON）

A.It is possible to have multiple database writers in an Oracle instance.
B.It writes dirty buffers， if any， to data files whenever a checkpoint occurs.
C.It writes dirty buffers， if any， to data files whenever a transaction commits.
D.It writes dirty buffers， if any， to data files before the log writer （LGWR） writes.

A.Checkpoint （CKPT）
B.Process Monitor （PMON）
C.Archiver Processes （ARCn）
D.Recoverer Process （RECO）
E.Memory Manager process （MMAN）