Wednesday 11 February 2015

Data Warehousing Technical Interview Questions and Answers (Page 7)

Below are some important Data Warehouse interview questions which are asked in most MNC company interviews for beginners or professionals.

61. What is a full backup?

A full backup is an operating system backup of all data files, on- line redo log files and control file that constitute ORACLE database and the parameter.

62. What is Mirrored on-line Redo Log?
A mirrored on-line redo log consists of copies of on-line redo log files physically located on separate disks; changes made to one member of the group are made to all members.

63. What is Partial Backup?
A Partial Backup is any operating system backup short of a full backup, taken while the database is open or shut down.

64. What is Restricted Mode of Instance Startup?
An instance can be started in (or later altered to be in) restricted mode so that when the database is open connections are limited only to those whose user accounts have been granted the RESTRICTED SESSION system privilege.

65. What is Archived Redo Log?
Archived Redo Log consists of Redo Log files that have archived before being reused.

66. What are the steps involved in Database Shutdown?
Close the Database; Dismount the Database and Shutdown the Instance.

67. What are the advantages of operating a database in ARCHIVELOG mode over operating it in NO ARCHIVELOG mode?
Complete database recovery from disk failure is possible only in ARCHIVELOG mode. Online database backup is possible only in ARCHIVELOG mode.

68. What are the different modes of mounting a Database with the Parallel Server?
Exclusive Mode If the first instance that mounts a database does so in exclusive mode, only that Instance can mount the database. Parallel Mode If the first instance that mounts a database is started in parallel mode, other instances that are started in parallel mode can also mount the database.

69. Can Full Backup be performed when the database is open?
No

70. What are the steps involved in Instance Recovery?
Rolling forward to recover data that has not been recorded in data files yet has been recorded in the on-line redo log, including the contents of rollback segments.
Rolling back transactions that have been explicitly rolled back or have not been committed as indicated by the rollback segments regenerated in step a.
1) Releasing any resources (locks) held by transactions in process at the time of the failure.
2) Resolving any pending distributed transactions undergoing a two-phase commit at the time of the instance failure.
More Questions & Answers :-
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