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GK One-Line Question & Answer

15541+ short questions with short answers, covering every category and sub-category on the site — no long articles to scroll through. Good for a fast recap before an exam, or a few minutes of daily practice.

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DBMS → Relational Model 3

Which is a duplicate copy of a file program that is stored on a different storage media than the original location:
backup
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Which of the following are introduced to reduce the overheads caused by the log- based recovery?
checkpoints
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The                      requires that each transaction Ti executes in two or three different phases in its lifetime, depending on whether it is a read-only or an update transaction.
validation protocol
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DBMS → Normalization 3

Which is the duplication of computer operations and routine backups to combat any unforeseen problems:
recovery
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Which of the following protocols ensures conflict serializability and safety from deadlocks?
time-stamp ordering protocol
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                         denotes the largest timestamp of any transaction that executed write(Q) successfully.
w-timestamp(q)
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DBMS → Functional Dependency 3

Optimization basically related to the Rewrite module is termed as               
semantic query optimization
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Which refers to a property of computer to run several operation simultaneously and possible as computers await response of each other
concurrency
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The most recent version of standard SQL prescribed by the American National Standards Institute is
sql 2016
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DBMS → SQL Basics 3

Database security helps organizations to protect data from            
external users
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The          lock allows concurrent transactions to access the same row as long as they require the use of different fields within that row.
field-level
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ANSI-standard SQL allows the use of special operators in conjunction with the WHERE clause. A special operator used to check whether an attribute value is null is
is null
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DBMS → DDL Commands 2

Copying files to secondary or specific devices is known as              
backup
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Which of the following is a procedure for acquiring the necessary locks for a transaction where all necessary locks are acquired before any are released?
two phase lock
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DBMS → DML Commands 2

Which are types of recovery control techniques:
all of the mentioned
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A system is in a              state if there exists a set of transactions such that every transaction in the set is waiting for another transaction in the set.
deadlock
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DBMS → Joins 2

Which server can join the indexes when only multiple indexes combined can cover the query:
sql
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The deadlock state can be changed back to stable state by using                             statement.
rollback
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DBMS → Views 2

In concurrency control policy the lock is obtained on
entire database
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What are the ways of dealing with deadlock?
all of the mentioned
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DBMS → Indexes 2

A concurrency-control policy such as this one leads to              performance since it forces transactions to wait for preceding transactions to finish before they can start.
poor
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When transaction Ti requests a data item currently held by Tj, Ti is allowed to wait only if it has a timestamp smaller than that of Tj (that is, Ti is older than Tj). Otherwise, Ti is rolled back (dies). This is
wait-die
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DBMS → Transactions 2

                     are used to ensure that transactions access each data item in order of the transactions’          if their accesses conflict.
timestamps
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When transaction Ti requests a data item currently held by Tj, Ti is allowed to wait only if it has a timestamp larger than that of Tj (that is, Ti is younger than Tj ). Otherwise, Tj is rolled back (Tj is wounded by Ti). This is
wound-wait
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DBMS → Concurrency Control 2

In which scenario would you use the ROLLUP operator for expression or columns within a GROUP BY clause?
to create a grouping for expressions or columns specified within a group by clause in one direction, from right to left for calculating the subtotals
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The situation where the lock waits only for a specified amount of time for another lock to be released is
lock timeout
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DBMS → Deadlock 2

Which statement is true regarding external tables?
the create table as select statement can be used to unload data into regular table in the database from an external table
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The deadlock in a set of a transaction can be determined by
read-only graph
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DBMS → Database Security 2

SNAPSHOT is used for (DBA)
dynamic data replication
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A deadlock exists in the system if and only if the wait-for graph contains a                        
cycle
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DBMS → PL/SQL 2

Isolation of the transactions is ensured by
concurrency control
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                     rollback requires the system to maintain additional information about the state of all the running transactions.
partial
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DBMS → Introduction to DBMS 2

Which of the following statements is/are not true for SQL profiler?
check the performance of a stored procedure
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If a node is locked in an intention mode, explicit locking is done at a lower level of the tree. This is called
intention lock modes
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DBMS → Database Architecture 2

Which of the following is the original purpose of SQL?
all of the mentioned
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If a node is locked in                      explicit locking is being done at a lower level of the tree, but with only shared-mode locks.
intention lock modes
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DBMS → Data Models 2

SQL can be used to:
all of the mentioned
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If a node is locked in                          then explicit locking is being done at a lower level, with exclusive-mode or shared-mode locks.
intention-exclusive (ix) mode
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DBMS → ER Model 2

A lock that allows concurrent transactions to access different rows of the same table is known as a
row-level lock
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If a node is locked in                              the subtree rooted by that node is locked explicitly in shared mode, and that explicit locking is being done at a lower level with exclusive-mode locks.
shared and intention-exclusive (six) mode
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