Question 1

What does a VLAN do?

Accepted Answer

virtual LAN (VLAN) is any broadcast domain that is partitioned and isolated in a computer network at the data link layer (OSI layer 2). LAN is the abbreviation for local area network and in this context, virtual refers to a physical object recreated and altered by additional logic. VLANs work by applying tags to network packets and handling these tags in networking systems – creating the appearance and functionality of network traffic that is physically on a single network but acts as if it is split between separate networks. In this way, VLANs can keep network applications separate despite being connected to the same physical network, and without requiring multiple sets of cabling and networking devices to be deployed.

Question 2

Which standard govern parallel communications?

Accepted Answer

IEEE 1284

Question 3

What is meant by a dedicated computer?

Accepted Answer

Which is assigned one and only one task

Question 4

Which among the following are the capabilities of the Cursor?

Accepted Answer

All the above listed actions are the functions of cursor

Question 5

What is a DBA?

Accepted Answer

A DBA is a Database Administrator, and this is the most common job that you find a database specialist doing There are Development DBAs and Production DBAs - A Development DBA usually works closely with a team of developers and gets more involved in design decisions, giving advice on performance and writing good SQL That can be satisfying at a human level because you are part of a team and you share the satisfaction of the teams accomplishments - A Production DBA (on the other hand) is responsible for maintaining Databases within an organization, so it is a very difficult and demanding job He or she, often gets involved when all the design decisions have been made, and has simply to keep things up and running Therefore, of course, it is also a rewarding job, both financially and in terms of job satisfaction But it is a more "lonely" job than being a Development DBA

Question 6

What are the advantages of operating a database in ARCHIVELOG mode over operating it in NO ARCHIVELOG mode?

Accepted Answer

Complete database recovery from disk failure is possible only in ARCHIVELOG mode Online database backup is possible only in ARCHIVELOG mode

Question 7

What are the Referential actions supported by FOREIGN KEY integrity constraint?

Accepted Answer

UPDATE and DELETE Restrict - A referential integrity rule that disallows the update or deletion of referenced data DELETE Cascade - When a referenced row is deleted all associated dependent rows are deleted

Question 8

A table is classified as a parent table and you want to drop and re-create it. How would you do this without affecting the children tables?

Accepted Answer

Disable the foreign key constraint to the parent, drop the table, re-create the table, enable the foreign key constraint

Question 9

How would you go about increasing the buffer cache hit ratio?

Accepted Answer

Use the buffer cache advisory over a given workload and then query the v$db_cache_advice table If a change was necessary then I would use the alter system set db_cache_size command

Question 10

Explain an ORA-01555?

Accepted Answer

You get this error when you get a snapshot too old within rollback It can usually be solved by increasing the undo retention or increasing the size of rollbacks You should also look at the logic involved in the application getting the error message

Question 11

What does a Control file Contain?

Accepted Answer

A Control file records the physical structure of the database It contains the following information Database Name ,Names and locations of a database’s files and redolog files Time stamp of database creation

Question 12

Describe what redo logs are.

Accepted Answer

Redo logs are logical and physical structures that are designed to hold all the changes made to a database and are intended to aid in the recovery of a database

Question 13

How would you force a log switch?

Accepted Answer

ALTER SYSTEM SWITCH LOGFILE;

Question 14

What does coalescing a tablespace do?

Accepted Answer

Coalescing is only valid for dictionary-managed tablespaces and de-fragments space by combining neighboring free extents into large single extents

Question 15

How do you add a data file to a tablespace?

Accepted Answer

ALTER TABLESPACE ADD DATAFILE SIZE

Question 16

How do you resize a data file?

Accepted Answer

ALTER DATABASE DATAFILE RESIZE ;

Question 17

How can you rebuild an index?

Accepted Answer

ALTER INDEX REBUILD;

Question 18

How can you enable a trace for a session?

Accepted Answer

Use the DBMS_SESSIONSET_SQL_TRACE or Use ALTER SESSION SET SQL_TRACE = TRUE;

Question 19

What is Distributed database?

Accepted Answer

A distributed database is a network of databases managed by multiple database servers that appears to a user as single logical database The data of all databases in the distributed database can be simultaneously accessed and modified

Question 20

What is database clusters?

Accepted Answer

Group of tables physically stored together because they share common columns and are often used together is called Cluster

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