0

databases Online Quiz - 134

Description: databases Online Quiz - 134
Number of Questions: 20
Created by:
Tags: databases
Attempted 0/20 Correct 0 Score 0
  1. Values must be obtained from a lookup table.

  2. Values must be part of a fixed set defined by create or alter table.

  3. Values must include reserved words, such as SYSDATE and USER.

  4. The column cannot contain a NULL value.


Correct Option: B

The transaction control that prevents more than one user from updating data in a table is which of the following?

  1. lock

  2. commit

  3. rollback

  4. savepoint


Correct Option: A

AI Explanation

To answer this question, you need to understand transaction control in database management systems.

Option A) Lock - This option is correct because locks are used to prevent more than one user from updating data in a table simultaneously. Locks are acquired on the table or specific rows and are released after the transaction is complete.

Option B) Commit - This option is incorrect because the commit operation is used to permanently save the changes made during a transaction. It does not prevent multiple users from updating data simultaneously.

Option C) Rollback - This option is incorrect because the rollback operation is used to undo the changes made during a transaction and restore the database to its previous state. It does not prevent multiple users from updating data simultaneously.

Option D) Savepoint - This option is incorrect because savepoints are used to mark a specific point within a transaction to which it can be rolled back. It does not prevent multiple users from updating data simultaneously.

The correct answer is A) Lock. This option is correct because locks are used to prevent more than one user from updating data in a table simultaneously.

You are using SQL operations in Oracle. All of the following DATE functions return a DATE datatype except one. Which one is it?

  1. NEW_TIME

  2. LAST_DAY

  3. ADD_MONTHS

  4. MONTHS_BETWEEN


Correct Option: D

Which function can return a non-NULL value if passed a NULL argument?

  1. LENGTH

  2. CONCAT

  3. INSTR

  4. NULLIF


Correct Option: B

Which datatype stores data outside Oracle Database?

  1. UROWID

  2. BLOB

  3. NCLOB

  4. BFILE


Correct Option: D
  1. Primary key constraints allow NULL values in the columns.

  2. Unique key constraints allow NULL values in the columns.

  3. Primary key constraints do not allow NULL values in the columns.

  4. A nonunique index cannot be used to enforce primary key constraints.


Correct Option: B,C
  1. an integrated file system only

  2. A mirroring technology only

  3. an integrated file system with a volume manager

  4. A Volume manager only


Correct Option: C
  1. trace files

  2. cross paltform transportable datafiles

  3. change tracking file

  4. temporary files


Correct Option: A
  1. tablespace

  2. data blocks

  3. file

  4. extents


Correct Option: D

What is Oracle data guard?

  1. used for data refresh from Production env. to development env.

  2. used as security layer to protect data from unathorized access.

  3. An Oracle technology used for data protection through mirroring.

  4. It ensures high availability, data protection, and disaster recovery for enterprise data.


Correct Option: D

A Data Guard configuration contains one production database which is _____________

  1. a RAC database only

  2. a stand alone database only

  3. The primary database can be either a standalone database or a RAC.

  4. a physical standby database .


Correct Option: C
  1. redo transport service,log applyservice,Role transition

  2. log applyservice,Role transition,Failover service

  3. redo transport service,Role transition,Failover service

  4. redo transport service,log applyservice,Failover service


Correct Option: A
  1. Protection,availability,performance

  2. Protection,availability,scalability

  3. Maximum Protection,maximum availability,maximum performance

  4. Maximum Protection,maximum availability,maximum scalability


Correct Option: C

Which component in the SGA has the dictionary cache?

  1. Buffer cache

  2. Library cache

  3. Shared pool

  4. Program Global Area


Correct Option: C

What is the minimum number of control files are required to start a database?

  1. One

  2. Two

  3. Three

  4. None


Correct Option: A
- Hide questions