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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

Ranking of queries is done by which of the following?
order by
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Which is a join condition contains an equality operator:
equijoins
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Establishing limits on allowable property values, and specifying a set of acceptable, predefined options that can be assigned to a property are examples of:
data integrity constraints
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DBMS → Normalization 3

In rank() function if one value is shared by two tuples then
the rank order continues by leaving one rank in the middle
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Which of the following is not outer join?
all of the mentioned
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Which of the following can be addressed by enforcing a referential integrity constraint?
information on the customer must be known before anything can be sold to that customer
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DBMS → Functional Dependency 3

The                      function that does not create gaps in the ordering.
dense_rank()
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The assignment operator is denoted by
<-
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             is a special type of integrity constraint that relates two relations & maintains consistency across the relations.
referential integrity constraints
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DBMS → SQL Basics 3

If there are n tuples in the partition and the rank of the tuple is r, then its                  is defined as (r −1)/(n−1).
percent_rank
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Which of the following symbol is used in the place of except?
¬
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Which one of the following uniquely identifies the elements in the relation?
primary key
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DBMS → DDL Commands 2

Inorder to simplify the null value confusion in the rank function we can specify
either nulls last or first
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Which of the following is the comparison operator in tuple relational calculus
=
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DBMS → DML Commands 2

The command                                  such tables are available only within the transaction executing the query and are dropped when the transaction finishes.
create temporary table
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In domain relaional calculus “there exist”
Э x (p1(x))
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DBMS → Joins 2

OLAP stands for
online analytical processing
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A set of possible data values is called
domain
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DBMS → Views 2

The process of viewing the cross-tab (Single dimensional) with a fixed value of one attribute is
slicing
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An                  is a set of entities of the same type that share the same properties, or attributes.
entity set
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DBMS → Indexes 2

The operation of moving from finer- granularity data to a coarser granularity (by means of aggregation) is called a                  
rollup
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Entity is a                    
thing in real world
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DBMS → Transactions 2

In SQL the cross-tabs are created using
slice
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The attribute name could be structured as an attribute consisting of first name, middle initial, and last name. This type of attribute is called
composite attribute
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DBMS → Concurrency Control 2

What do data warehouses support?
olap
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The attribute AGE is calculated from DATE_OF_BIRTH. The attribute AGE is
derived
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DBMS → Deadlock 2

Which one of the following is the right syntax for DECODE?
decode (expression, search, result [, search, result]… [, default])
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Not applicable condition can be represented in relation entry as
null
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DBMS → Database Security 2

Relational Algebra is a                      query language that takes two relations as input and produces another relation as an output of the query.
procedural
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Which of the following can be a multivalued attribute?
phone_number
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DBMS → PL/SQL 2

Which of the following is a fundamental operation in relational algebra?
none of the mentioned
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Which of the following is a single valued attribute
register_number
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DBMS → Introduction to DBMS 2

Which of the following is used to denote the selection operation in relational algebra?
sigma (greek)
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In a relation between the entities the type and condition of the relation should be specified. That is called as            attribute.
desciptive
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DBMS → Database Architecture 2

For select operation the                  appear in the subscript and the                         argument appears in the paranthesis after the sigma.
predicates, relation
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                           express the number of entities to which another entity can be associated via a relationship set.
mapping cardinality
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DBMS → Data Models 2

The                        operation, denoted by −, allows us to find tuples that are in one relation but are not in another.
set-difference
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An entity in A is associated with at most one entity in B, and an entity in B is associated with at most one entity in A.This is called as
one-to-one
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DBMS → ER Model 2

Which is a unary operation:
generalized selection
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An entity in A is associated with at most one entity in B. An entity in B, however, can be associated with any number (zero or more) of entities in A.
many-to-one
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