307 + Interview Questions in GENERAL QA IN RDBMS Page 3 InterviewSolution

101.	The 3NF decomposition algorithm is also called as _______(a) 3NF normal algorithm(b) 3NF synthesis algorithm(c) 3NF generator(d) Functional dependence algorithm
Answer» Right answer is (b) 3NF synthesis algorithm Best explanation: The 3NF decomposition algorithm is also called as 3NF synthesis algorithm since it takes a set of dependencies and adds one schema at a time, instead of decomposing the initial schema repeatedly.

Discussion

102.	What does the BCNF decomposition algorithm do?(a) States a method to decompose a relation satisfying BCNF(b) States a method for joining two relations satisfying BCNF(c) States a method to decompose a relational schema such that there are no multiple occurrences(d) None of the mentioned
Answer» Correct choice is (a) States a method to decompose a relation satisfying BCNF For explanation I would say: If a relation is not in BCNF, it can be decomposed into simpler relations that are in BCNF. The BCNF decomposition algorithm states a method to decompose a relation satisfying BCNF.

Discussion

103.	Which of the following is not a condition for the third normal form in the case of XY?(a) X→ Y is trivial(b) X is the superkey for R(c) Each attribute in Y-X is a candidate key for R(d) Each attribute in X-Y is a candidate key for R
Answer» The correct answer is (d) Each attribute in X-Y is a candidate key for R To elaborate: Each attribute in X-Y is a candidate key for R is not a necessary condition for the third normal form in the case of X → Y. X→Y is trivial and X is the superkey of R are necessary conditions for the third normal form.

Discussion

104.	Which of the following normal forms does not exist?(a) BCNF(b) PJNF(c) 5NF(d) None of the mentioned
Answer» The correct option is (d) None of the mentioned The explanation: All of the mentioned normal forms i.e. BCNF, PJNF, 5NF exist. BCNF is Boyce Codd normal form, 5NF is the fifth normal form and PJNF is project join normal form.

Discussion

105.	Which of the following techniques does not exist?(a) Pipelined join technique(b) Left pipelined join technique(c) Right pipelined join technique(d) None of the mentioned
Answer» Right choice is (d) None of the mentioned Explanation: Pipelined join technique, both left and right are evaluation techniques that can be used to organize data.

Discussion

106.	F+ is called as the ________ of F(a) Closure(b) Sum(c) Cartesian product(d) None of the mentioned
Answer» Right choice is (a) Closure Best explanation: F+ is called as the closure of F. It contains all the possible combinations of a functional dependency set in it.

Discussion

107.	Which of the following is not a built in aggregate function in SQL?(a) avg(b) max(c) total(d) count
Answer» The correct choice is (c) total For explanation I would say: SQL does not include total as a built in aggregate function. The avg is used to find average, max is used to find the maximum and the count is used to count the number of values.

Discussion

108.	Which of the following correctly describes the between predicate in the where clause?(a) It is used to check whether a value is in between two specified values(b) It is used to check whether a value is exactly in the center of the relation alphabetically(c) It is used to check whether a value is in between any two other values in the database(d) None of the mentioned
Answer» Correct answer is (a) It is used to check whether a value is in between two specified values The best I can explain: The between predicate in the where clause is used to check whether a value is in between two externally specified values. This clause is used to list out all tuples having a value within a range.

Discussion

109.	The _________ of the entity set is an actual collection of entities belonging to that entity set.(a) Extension(b) Intention(c) Description(d) Availability
Answer» Correct choice is (a) Extension Easy explanation: The extension of the entity set is an actual collection of entities belonging to that entity set.

Discussion

110.	A selection of the form satisfying the union of all records satisfying individual simple conditions is(a) Conjunctive selection(b) Disjunctive selection(c) Negation(d) None of the mentioned
Answer» Correct choice is (b) Disjunctive selection Explanation: A selection of the form satisfying the intersection of all records satisfying individual simple conditions is a disjunctive selection. This is a form of complex selection predicate.

Discussion

111.	A selection of the form giving all the records not satisfying simple individual conditions is ______(a) Conjunctive selection(b) Disjunctive selection(c) Negation(d) None of the mentioned
Answer» Right choice is (c) Negation Explanation: A selection of the form giving all the records not satisfying simple individual conditions is negation. This is a form of complex selection predicate.

Discussion

112.	A selection of the form satisfying the intersection of all records satisfying individual simple conditions is(a) Conjunctive selection(b) Disjunctive selection(c) Negation(d) None of the mentioned
Answer» Right choice is (a) Conjunctive selection To elaborate: A selection of the form satisfying the intersection of all records satisfying individual simple conditions is a conjunctive selection. This is a form of complex selection predicate.

Discussion

113.	If each higher level entity belongs to the lower level entity, then what kind of generalization is it?(a) Modal generalization(b) Partial generalization(c) Total generalization(d) None of the mentioned
Answer» Correct answer is (c) Total generalization Easy explanation: If each higher level entity belongs to the lower level entity then it is called as total generalization. It is also called as total specialization. If some higher level entities do not belong, it is called as partial generalization.

Discussion

114.	Which of the following steps must be taken while choosing a victim?(a) Avoiding starvation(b) Number of transactions involved in rollback(c) Data items used by the transaction(d) All of the mentioned
Answer» The correct answer is (d) All of the mentioned The best I can explain: While choosing a victim we much choose the one with a minimum cost. That is the one which avoids starvation, the one with the least number of transaction involved in the rollback and the one with the least amount of data items used.

Discussion

115.	What is a view?(a) An brief description of the schema diagram.(b) A relation that is not a part of the schema but is a virtual relation(c) Any relation that is a part of the schema(d) A relation that is a part of the schema but which needs to be specified in every operation made on that particular relation.
Answer» Correct option is (b) A relation that is not a part of the schema but is a virtual relation Explanation: A relation that is not a part of the schema but is a virtual relation is called as view. Views improve writability as viewing the entire logical model is not feasible.

Discussion

116.	What is the result of the above query?(a) It creates a view named studentdet with 3 attributes(b) It creates a view named studentdet with 1 attribute(c) It creates a view named ID with 2 attributes(d) It is syntactically wrong and does not give a result
Answer» Right choice is (d) It is syntactically wrong and does not give a result Best explanation: immediately after specifying the name of the view, we have to write the “as” keyword. So this query does not give any result as it is syntactically incorrect.

Discussion

117.	________ allows only committed data to be read, but does not require repeatable reads(a) Read uncommitted(b) Serializable(c) Repeatable read(d) Read committed
Answer» Right answer is (d) Read committed The explanation: Read committed allows only committed data to be read, but does not require repeatable reads. For instance, between two reads of a data item by the transaction, another transaction may have updated the data item and committed.

Discussion

118.	W-timestamp(Q) denotes?(a) The largest timestamp of any transaction that can execute write(Q) successfully(b) The largest timestamp of any transaction that can execute read(Q) successfully(c) The smallest timestamp of any transaction that can execute write(Q) successfully(d) The smallest timestamp of any transaction that can execute read(Q) successfully
Answer» The correct choice is (a) The largest timestamp of any transaction that can execute write(Q) successfully Explanation: W-timestamp(Q) denotes The largest timestamp of any transaction that can execute write(Q) successfully.

Discussion

119.	Which of the following cannot be used to implement a timestamp(a) System clock(b) Logical counter(c) External time counter(d) None of the mentioned
Answer» The correct answer is (c) External time counter For explanation: An external time counter cannot be used to implement a timestamp. System clock and a logical counter can be used.

Discussion

120.	What is the command used to define view in SQL?(a) define view(b) new view(c) create view(d) none of the mentioned
Answer» The correct option is (c) create view To explain: We use the create view command to define a view in SQL.

Discussion

121.	If a query is optimized without providing specific values for its parameters the technique is called __________(a) Complex query handling(b) Multi query optimization(c) Complex query optimization(d) Parametric query optimization
Answer» Right answer is (d) Parametric query optimization Easy explanation: If a query is optimized without providing specific values for its parameters the technique is called parametric query optimization.

Discussion

122.	The “all-or-none” property is commonly referred to as _________(a) Isolation(b) Durability(c) Atomicity(d) None of the mentioned
Answer» The correct option is (c) Atomicity To elaborate: The all or none policy is commonly referred to as atomicity. It ensures that a work is either completed or not completed and there are no intermediate stages.

Discussion

123.	Collections of operations that form a single logical unit of work are called __________(a) Views(b) Networks(c) Units(d) Transactions
Answer» The correct option is (d) Transactions Explanation: Collections of operations that form a single logical unit of work are called transactions. A database system must ensure proper execution of transactions.

Discussion

124.	A sequence of primitive operations that can be used to evaluate a query are called as __________(a) Query evaluation algebra(b) Query evaluation plan(c) Query evaluation primitive(d) Query evaluation engine
Answer» Correct option is (b) Query evaluation plan For explanation: A sequence of primitive operations that can be used to evaluate a query are called as Query evaluation plan. This is used by the query evaluation engine to process the queries.

Discussion

125.	The rule that allows transformation of a logical operation to a physical operation is called(a) Logical equivalence rule(b) Physical equivalence rule(c) Memory equivalence rule(d) None of the mentioned
Answer» Correct answer is (b) Physical equivalence rule For explanation I would say: The rule that allows transformation of a logical operation to a physical operation is called as a physical equivalence rule. It is a new class of equivalence rules.

Discussion

126.	The logical to physical page mapping is represented in a ____________(a) Logic physical table(b) Transition table(c) Wear leveling table(d) Logic log table
Answer» Correct answer is (b) Transition table Easiest explanation: The logical to physical page mapping is represented in a Transition table which is generally available in memory. This is used for quick access of data.

Discussion

127.	A logical counter is _________ after a new timestamp has been assigned(a) Incremented(b) Decremented(c) Doubled(d) Remains the same
Answer» The correct option is (a) Incremented To explain I would say: A logical counter is incremented after a new timestamp has been assigned everytime.

Discussion

128.	Which of the following is not a relational algebra function?(a) Select(b) Project(c) Manipulate(d) Union
Answer» Right choice is (c) Manipulate Explanation: There does not exist any operation named as manipulate operation in relational algebra. The union gives the union of two sets. Project is similar to select in SQL and select is similar to where in SQL.

Discussion

129.	The select operation’s function in relational algebra is identical to the _______ clause in SQL(a) where(b) from(c) select(d) none of the mentioned
Answer» Correct choice is (a) where Easiest explanation: The select operation’s function in relational algebra is identical to the where clause in SQL standard. It is therefore used to check for a particular condition.

Discussion

130.	Most databases store the distribution of values for each attribute as a __________(a) Histogram(b) Pie chart(c) Line graph(d) None of the mentioned
Answer» Correct choice is (a) Histogram The explanation is: Most of the databases store the distribution of values for each attribute as a histogram.in which the values for the attributes are divided into various ranges.

Discussion

131.	Choose the correct statement regarding superkeys(a) A superkey is an attribute or a group of multiple attributes that can uniquely identify a tuple(b) A superkey is a tuple or a set of multiple tuples that can uniquely identify an attribute(c) Every superkey is a candidate key(d) A superkey is an attribute or a set of attributes that distinguish the relation from other relations
Answer» Correct option is (a) A superkey is an attribute or a group of multiple attributes that can uniquely identify a tuple The explanation: A superkey is an attribute or a set of multiple attributes that can uniquely identify a tuple. It is used to differentiate between tuples.

Discussion

132.	An attribute is a __________ in a relation.(a) Row(b) Column(c) Value(d) Tuple
Answer» The correct option is (b) Column For explanation: An attribute is a column in a relation. A tuple is a row in a relation.

Discussion

133.	A _________ on the attribute A of relation r consists of one bitmap for each value that A can take(a) Bitmap array(b) Bitmap index(c) Bitmap excess(d) Bitmap
Answer» Right option is (b) Bitmap index For explanation: A bitmap index on the attribute A of relation r consists of one bitmap for each value that A can take. Each bitmap contains as many bits as the number of records in the relation.

Discussion

134.	If B is an attribute and A→B, Then B is said to be ________ by a.(a) Logically implied(b) Functionally implied(c) Logically determined(d) Functionally determined
Answer» The correct option is (d) Functionally determined To explain: If B is an attribute and A→B, Then B is said to be functionally determined by a.

Discussion

135.	Size estimation can be done for which of the following processes?(a) Projection(b) Aggregation(c) Set operation(d) All of the mentioned
Answer» Right choice is (d) All of the mentioned The best explanation: Size estimation can be done for projection, aggregation, set operations, join operations and also the selection operation.

Discussion

136.	What is a foreign key?(a) A foreign key is a primary key of a relation which is an attribute in another relation(b) A foreign key is a superkey of a relation which is an attribute in more than one other relations(c) A foreign key is an attribute of a relation that is a primary key of another relation(d) A foreign key is the primary key of a relation that does not occur anywhere else in the schema
Answer» Correct answer is (c) A foreign key is an attribute of a relation that is a primary key of another relation The explanation is: A foreign key is an attribute of a relation that is initially a primary key of another relation. A foreign key usage preserves referential integrity.

Discussion

137.	The _________ graph describes deadlocks precisely(a) Wound wait graph(b) Wait die graph(c) Wait for graph(d) None of the mentioned
Answer» The correct option is (c) Wait for graph For explanation I would say: The wait for graph describes deadlocks precisely. Existence of a cycle in this graph implies that a deadlock will occur.

Discussion

138.	The ________ comparison checker is used to check “each and every” condition(a) all(b) and(c) every(d) each
Answer» The correct answer is (a) all For explanation: The all comparison checker is used to check “each and every” condition. The “each” and “every” comparison checkers do not exist in SQL.

Discussion

139.	Scalar Subqueries can be used in the SQL update statement when they are used under the ____ clause(a) where(b) with(c) set(d) end
Answer» Correct answer is (c) set To explain I would say: SQL subqueries that can occur wherever a value is permitted provided the subquery gives only one tuple with a single attribute are called Scalar subqueries. Scalar Subqueries can be used in the SQL update statement when they are used under the set clause.

Discussion

140.	SQL subqueries that can occur wherever a value is permitted provided the subquery gives only one tuple with a single attribute are called _________(a) Exact Subqueries(b) Vector Subqueries(c) Positive Subqueries(d) Scalar Subqueries
Answer» The correct choice is (d) Scalar Subqueries The explanation is: SQL subqueries that can occur wherever a value is permitted provided the subquery gives only one tuple with a single attribute are called Scalar subqueries. Scalar Subqueries can be used in the SQL update statement when they are used under the set clause.

Discussion

141.	If a set is a collection of values given by the select clause, The ______ connective tests for set membership(a) within(b) include(c) under(d) in
Answer» Correct option is (d) in Best explanation: The in connective is used to test for the membership in a set, where the set is a collection of values given by the select clause.

Discussion

142.	Caching and reuse of query plans is called as ________(a) Query caching(b) Plan caching(c) Plan memorizing(d) None of the mentioned
Answer» Correct option is (b) Plan caching Easy explanation: Caching and reuse of query plans is called as plan caching. It is used because the optimal plan for the new constants may differ from the optimal plan for the initial values.

Discussion

143.	A ________ explores the space of all query evaluation plans that are equivalent to a given query.(a) Cost based optimizer(b) Space based optimizer(c) Time based optimizer(d) None of the mentioned
Answer» Correct option is (a) Cost based optimizer Explanation: A cost based optimizer explores the space of all query evaluation plans that are equivalent to a given query, and chooses the one with the least estimated cost.

Discussion

144.	What is a correlated sub-query?(a) An independent query that uses the correlation name of another independent query.(b) A sub-query that uses the correlation name of an outer query(c) A sub-query that substitutes the names of the outer query(d) A sub-query that does not depend on its outer query’s correlation names
Answer» Right answer is (b) A sub-query that uses the correlation name of an outer query The best I can explain: A correlated sub-query is the one that uses the correlation name of an outer query.

Discussion

145.	Which of the following commands do we use to delete a relation (R) from a database?(a) drop table R(b) drop relation R(c) delete table R(d) delete from R
Answer» Correct choice is (a) drop table R Best explanation: The drop table command is used to delete a relation from a database whereas the delete table removes all the tuples from a re

Discussion

146.	How do we generally recover from a deadlock?(a) By aborting all the transactions(b) By rolling back all the transactions(c) By rolling back only a selected number of transactions(d) None of the mentioned
Answer» Right option is (c) By rolling back only a selected number of transactions Explanation: We generally recover from deadlocks by rolling back only a selected number of transactions

Discussion

147.	Javascript is used to create dynamic webpages using technologies that are collectively called ________(a) Ajax(b) Thor(c) Dynamo(d) Achilles
Answer» The correct option is (a) Ajax The best I can explain: Javascript is used to create dynamic webpages using technologies that are collectively called Ajax.

Discussion

148.	Which of the following is not a method in deadlock handling(a) Deadlock prevention(b) Deadlock detection(c) Deadlock recovery(d) Deadlock distribution
Answer» Correct option is (d) Deadlock distribution Easiest explanation: Deadlock distribution is not a method in deadlock handling whereas, deadlock prevention is followed by deadlock detection and deadlock recovery.

Discussion

149.	What is the syntax to load data into the database? (Consider D as the database and a, b, c as data)(a) enter into D (a, b, c);(b) insert into D values (a, b, c);(c) insert into D (a, b, c);(d) insert (a, b, c) values into D;
Answer» Correct answer is (b) insert into D values (a, b, c); To explain I would say: To load data into a database we use the insert into command. The syntax is insert into D values (a, b, c) where a, b, c are the appropriate values

Discussion

150.	The sequence of queries that reflect the typical load on the system are known as ________(a) Efficacies(b) Workload(c) Selection(d) Balancers
Answer» The correct choice is (b) Workload The best I can explain: The sequence of queries that reflect the typical workload on the system are known as workload.

Discussion

Explore topic-wise InterviewSolutions in .

The 3NF decomposition algorithm is also called as _______(a) 3NF normal algorithm(b) 3NF synthesis algorithm(c) 3NF generator(d) Functional dependence algorithm

What does the BCNF decomposition algorithm do?(a) States a method to decompose a relation satisfying BCNF(b) States a method for joining two relations satisfying BCNF(c) States a method to decompose a relational schema such that there are no multiple occurrences(d) None of the mentioned

Which of the following is not a condition for the third normal form in the case of XY?(a) X→ Y is trivial(b) X is the superkey for R(c) Each attribute in Y-X is a candidate key for R(d) Each attribute in X-Y is a candidate key for R

Which of the following normal forms does not exist?(a) BCNF(b) PJNF(c) 5NF(d) None of the mentioned

Which of the following techniques does not exist?(a) Pipelined join technique(b) Left pipelined join technique(c) Right pipelined join technique(d) None of the mentioned

F+ is called as the ________ of F(a) Closure(b) Sum(c) Cartesian product(d) None of the mentioned

Which of the following is not a built in aggregate function in SQL?(a) avg(b) max(c) total(d) count

The _________ of the entity set is an actual collection of entities belonging to that entity set.(a) Extension(b) Intention(c) Description(d) Availability

A selection of the form satisfying the union of all records satisfying individual simple conditions is(a) Conjunctive selection(b) Disjunctive selection(c) Negation(d) None of the mentioned

A selection of the form giving all the records not satisfying simple individual conditions is ______(a) Conjunctive selection(b) Disjunctive selection(c) Negation(d) None of the mentioned

A selection of the form satisfying the intersection of all records satisfying individual simple conditions is(a) Conjunctive selection(b) Disjunctive selection(c) Negation(d) None of the mentioned

If each higher level entity belongs to the lower level entity, then what kind of generalization is it?(a) Modal generalization(b) Partial generalization(c) Total generalization(d) None of the mentioned

Which of the following steps must be taken while choosing a victim?(a) Avoiding starvation(b) Number of transactions involved in rollback(c) Data items used by the transaction(d) All of the mentioned

What is the result of the above query?(a) It creates a view named studentdet with 3 attributes(b) It creates a view named studentdet with 1 attribute(c) It creates a view named ID with 2 attributes(d) It is syntactically wrong and does not give a result

________ allows only committed data to be read, but does not require repeatable reads(a) Read uncommitted(b) Serializable(c) Repeatable read(d) Read committed

Which of the following cannot be used to implement a timestamp(a) System clock(b) Logical counter(c) External time counter(d) None of the mentioned

What is the command used to define view in SQL?(a) define view(b) new view(c) create view(d) none of the mentioned

If a query is optimized without providing specific values for its parameters the technique is called __________(a) Complex query handling(b) Multi query optimization(c) Complex query optimization(d) Parametric query optimization

The “all-or-none” property is commonly referred to as _________(a) Isolation(b) Durability(c) Atomicity(d) None of the mentioned

Collections of operations that form a single logical unit of work are called __________(a) Views(b) Networks(c) Units(d) Transactions

A sequence of primitive operations that can be used to evaluate a query are called as __________(a) Query evaluation algebra(b) Query evaluation plan(c) Query evaluation primitive(d) Query evaluation engine

The rule that allows transformation of a logical operation to a physical operation is called(a) Logical equivalence rule(b) Physical equivalence rule(c) Memory equivalence rule(d) None of the mentioned

The logical to physical page mapping is represented in a ____________(a) Logic physical table(b) Transition table(c) Wear leveling table(d) Logic log table

A logical counter is _________ after a new timestamp has been assigned(a) Incremented(b) Decremented(c) Doubled(d) Remains the same

Which of the following is not a relational algebra function?(a) Select(b) Project(c) Manipulate(d) Union

The select operation’s function in relational algebra is identical to the _______ clause in SQL(a) where(b) from(c) select(d) none of the mentioned

Most databases store the distribution of values for each attribute as a __________(a) Histogram(b) Pie chart(c) Line graph(d) None of the mentioned

An attribute is a __________ in a relation.(a) Row(b) Column(c) Value(d) Tuple

A _________ on the attribute A of relation r consists of one bitmap for each value that A can take(a) Bitmap array(b) Bitmap index(c) Bitmap excess(d) Bitmap

If B is an attribute and A→B, Then B is said to be ________ by a.(a) Logically implied(b) Functionally implied(c) Logically determined(d) Functionally determined

Size estimation can be done for which of the following processes?(a) Projection(b) Aggregation(c) Set operation(d) All of the mentioned

The _________ graph describes deadlocks precisely(a) Wound wait graph(b) Wait die graph(c) Wait for graph(d) None of the mentioned

The ________ comparison checker is used to check “each and every” condition(a) all(b) and(c) every(d) each

Scalar Subqueries can be used in the SQL update statement when they are used under the ____ clause(a) where(b) with(c) set(d) end

SQL subqueries that can occur wherever a value is permitted provided the subquery gives only one tuple with a single attribute are called _________(a) Exact Subqueries(b) Vector Subqueries(c) Positive Subqueries(d) Scalar Subqueries

If a set is a collection of values given by the select clause, The ______ connective tests for set membership(a) within(b) include(c) under(d) in

Caching and reuse of query plans is called as ________(a) Query caching(b) Plan caching(c) Plan memorizing(d) None of the mentioned

A ________ explores the space of all query evaluation plans that are equivalent to a given query.(a) Cost based optimizer(b) Space based optimizer(c) Time based optimizer(d) None of the mentioned

Which of the following commands do we use to delete a relation (R) from a database?(a) drop table R(b) drop relation R(c) delete table R(d) delete from R

How do we generally recover from a deadlock?(a) By aborting all the transactions(b) By rolling back all the transactions(c) By rolling back only a selected number of transactions(d) None of the mentioned

Javascript is used to create dynamic webpages using technologies that are collectively called ________(a) Ajax(b) Thor(c) Dynamo(d) Achilles

Which of the following is not a method in deadlock handling(a) Deadlock prevention(b) Deadlock detection(c) Deadlock recovery(d) Deadlock distribution

What is the syntax to load data into the database? (Consider D as the database and a, b, c as data)(a) enter into D (a, b, c);(b) insert into D values (a, b, c);(c) insert into D (a, b, c);(d) insert (a, b, c) values into D;

The sequence of queries that reflect the typical load on the system are known as ________(a) Efficacies(b) Workload(c) Selection(d) Balancers