Upgrade to Oracle Database 12c Free Sample Questions

B,D,E

A,D

A

A,B,C--Expiration:
A: You can create and rebuild indexes online. Therefore, you can update base tables at the same time you are building or rebuilding indexes on that table. You can perform DML operations while the index build is taking place, but DDL operations are not allowed. Parallel execution is not supported when creating or rebuilding an index online.
D: Moving (Rebuilding) Index-Organized Tables Because index-organized tables are primarily stored in a B-tree index, you can encounter fragmentation as a consequence of incremental updates. However, you can use the ALTER TABLE...MOVE statement to rebuild the index and reduce this fragmentation.
C: If a table can be compressed in the new tablespace, also it can be compressed in the same tablespace.
Incorrect answers:
B: Local and Global indexes can be automatically rebuild with UPDATE INDEXES when you move the table.--
References: http://www.oracle.com/technetwork/issue-archive/2014/14-may/o34dba-2193424.html

B,C,D

C

A--Explanation:

• Oracle Database provides a mechanism to make table structure modifications without significantly affecting the availability of the table. The mechanism is called online table redefinition. Redefining tablef^nline provides a substantial increase in availability compared to traditional methods of redefining tables.
• To redefine a table online: Choose the redefinition method: by key or by rowid
• By key—Select a primary key or pseudo-primary key to use for the redefinition. Pseudo-primary keys are unique keys with all component columns having NOT NULL constraints. For this method, the versions of the tables before and after redefinition should have the same primary key columns. This is the preferred and default method of redefinition. * By rowid—Use this method if no key is available. In this method, a hidden column named M_ROW$$ is added to the post-redefined version of the table. It is recommended that this column be dropped or marked as unused after the redefinition is complete. If COMPATIBLE is set to 10.2.0 or higher, the final phase of redefinition automatically sets this column unused. You can then use the ALTER TABLE ... DROP UNUSED COLUMNS statement to drop it.
  You cannot use this method on index-organized tables.
  Note: * When you rebuild an index, you use an existing index as the data source. Creating an index in this manner enables you to change storage characteristics or move to a new tablespace. Rebuilding an index based on an existing data source removes intra-block fragmentation. Compared to dropping the index and using the CREATE INDEX statement, re-creating an existing index offers better performance.
  Incorrect answers:
  E: Edition-based redefinition enables you to upgrade the database component of an application while it is in use, thereby minimizing or eliminating down time.

B,C,E--Explanation:
A: In a cumulative level 1 backup, RMAN backs up all the blocks used since the most recent level 0 incremental backup.
E: Oracle Block Change Tracking Once enabled; this new 10g feature records the modified since last backup and stores the log of it in a block change tracking file using the CTW (Change Tracking Writer) process. During backups RMAN uses the log file to identify the specific blocks that must be backed up. This improves RMAN's performance as it does not have to scan whole datafiles to detect changed blocks. Logging of changed blocks is performed by the CTRW process which is also responsible for writing data to the block change tracking file.
Note: * An incremental level 0 backup backs up all blocks that have ever been in use in this database.

B,C

A,C,E