Tag: databases

Questions Related to databases

  1. It is possible to have tablespaces of different block sizes in a database.

  2. A data block is the smallest unit of I/O for data files.

  3. Multiple tablespaces can share single data file.

  4. Each data block in the database always corresponds to one OS block.

  5. Each segment contains one or more extents.


Correct Option: A,B,E
  1. Data files and redo log files can be renamed at the MOUNT stage.

  2. Control files are required to bring the database to the NOMOUNT stage.

  3. Data files and online redo log files are checked for consistency while opening the database.

  4. Data files and redo log files are made available to users at the OPEN stage.

  5. Control files are read at the OPEN stage for the location of data files.


Correct Option: A,B,D
  1. USERS

  2. TOOLS

  3. UNDO

  4. INDEX

  5. SYSTEM


Correct Option: C,E
Explanation:

To solve this question, the user needs to know about the concept of tablespaces and recovery methods in Oracle database.

Closed recovery is a type of database recovery method in which all the data files of the database are restored from a backup and then the redo logs are applied to bring the database to a consistent state. Closed recovery is required when the database is in a state of complete failure and no data is available in the memory structures.

Only those tablespaces whose data files are so critical that they cannot be recovered using an open recovery method require a closed recovery.

Now, let's go through each option and identify if it requires a closed recovery or not:

A. USERS: This tablespace contains the user's data. It does not require a closed recovery if it gets damaged because it can be restored using an open recovery method.

B. TOOLS: This tablespace contains the database tools data. It does not require a closed recovery if it gets damaged because it can be restored using an open recovery method.

C. UNDO: This tablespace contains the undo data. It does not require a closed recovery if it gets damaged because it can be restored using an open recovery method.

D. INDEX: This tablespace contains the database index data. It does not require a closed recovery if it gets damaged because it can be restored using an open recovery method.

E. SYSTEM: This tablespace contains the system data. It is critical to the functioning of the database. If its data files are damaged, a closed recovery is required to restore it from a backup.

Therefore, the correct answer is:

The Answer is: E (SYSTEM)

Data files of which three tablespaces can be recovered by performing an open recovery?

  1. TEMP

  2. UNDO

  3. INDEX

  4. SYSAUX

  5. SYSTEM


Correct Option: A,C,D
  1. It creates the pointer file

  2. It creates the base directory

  3. It creates the inventory pointer file

  4. It creates the oracle user for installation.

  5. It modifies the UNIX kernel parameters to match oracle’s requirements.


Correct Option: C
  1. backup set only

  2. image copy only

  3. only user-managed backup

  4. both image copy and backup set

  5. only incremental image copy backup


Correct Option: A
  1. uses undo data for roll forward

  2. uses flashback log for recovery

  3. uses online redo logs to roll back

  4. uses undo data to roll back the transaction

  5. uses recovery managers (RMAN) to roll back.


Correct Option: D
  1. Group 2 is the active group

  2. Group 2 is the current group

  3. Database is in the MOUNT stage

  4. Group 2 has been already archived


Correct Option: D