Quick Revision

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 → Concurrency Control 3

To remove a relation from an SQL database, we use the              command.
drop table
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Aggregate functions are functions that take a                        as input and return a single value.
collection of values
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Which of the following creates a virtual relation for storing the query?
view
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DBMS → Deadlock 3

Updates that violate                      are disallowed.
integrity constraints
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A Boolean data type that can take values true, false, and                 
unknown
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Materialised views make sure that
view definition is kept up-to-date
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DBMS → Database Security 3

The              clause allows us to select only those rows in the result relation of the           clause that satisfy a specified predicate.
where, from
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The          connective tests for set membership, where the set is a collection of values produced by a select clause. The           connective tests for the absence of set membership.
in, not in
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Updating the value of the view
will affect the relation from which it is defined
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DBMS → PL/SQL 3

The                  clause is used to list the attributes desired in the result of a query.
select
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The phrase “greater than at least one” is represented in SQL by            
> some
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Which of the following is used at the end of the view to reject the tuples which do not satisfy the condition in where clause?
with check
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DBMS → Introduction to DBMS 2

Which of the following statements contains an error?
select empid where empid = 1009 and lastname = ‘geller’;
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SQL applies predicates in the                 clause after groups have been formed, so aggregate functions may be used.
with
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DBMS → Database Architecture 2

In SQL the spaces at the end of the string are removed by                function.
trim
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The                  keyword is used to access attributes of preceding tables or subqueries in the from clause.
lateral
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DBMS → Data Models 2

The union operation is represented by
u
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Which of the following creates a temporary relation for the query on which it is defined?
with
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DBMS → ER Model 2

The intersection operator is used to get the            tuples.
common
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Subqueries cannot:
join tables
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DBMS → Relational Model 2

If we want to retain all duplicates, we must write                  in place of union.
union all
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The EXISTS keyword will be true if:
any row in the subquery meets the condition only
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DBMS → Normalization 2

The number of attributes in relation is called as its
degree
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How can you find rows that do not match some specified condition?
double use of not exists
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DBMS → Functional Dependency 2

           clause is an additional filter that is applied to the result.
having
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Which one of the following deletes all the entries but keeps the structure of the relation.
delete from instructor;
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DBMS → SQL Basics 2

                   joins are SQL server default
inner
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The problem of ordering the update in multiple updates is avoided using
case
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DBMS → DDL Commands 2

The                            is essentially used to search for patterns in target string.
like predicate
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The        condition allows a general predicate over the relations being joined.
on
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DBMS → DML Commands 2

A            indicates an absent value that may exist but be unknown or that may not exist at all.
null value
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How many tables may be included with a join?
all of the mentioned
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DBMS → Joins 2

If the attribute phone number is included in the relation all the values need not be entered into the phone number column. This type of entry is given as
null
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Which are the join types in join condition:
all of the mentioned
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DBMS → Views 2

The predicate in a where clause can involve Boolean operations such as and. The result of true and unknown is               false and unknown is            while unknown and unknown is            
unknown, false, unknown
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How many join types in join condition:
5
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DBMS → Indexes 2

Using the              clause retains only one copy of such identical tuples.
distinct
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The operation which is not considered a basic operation of relational algebra is
join
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DBMS → Transactions 2

The result of           unknown is unknown.
not
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In SQL the statement select * from R, S is equivalent to
select * from r cross join s
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