DBMS Question Paper-GATE & PSU Exam

/ Previous Year Questions / GATE CSE, Nielit Exam, Previous Year Questions, PSU pyqs

Here, We will see DBMS Question Paper from the previous year’s exam and the syllabus of DBMS for the GATE and PSU Exam.

1. DBMS (Database Management System)

DBMS(Database Management System) evaluates a candidate’s understanding of database management systems (DBMS), focusing on design, implementation, and optimization. This subject tests theoretical knowledge and practical problem-solving skills through questions on relational models, SQL, transactions, and more.

2. DBMS Syllabus

The DBMS Questions asked in the GATE and PSU Exam focused on topics

  1. Data Modeling: ER diagrams, relational algebra, and tuple calculus.
  2. Relational Databases: Integrity constraints, SQL queries, and normalization (1NF to BCNF).
  3. Storage and Indexing: File organization, B/B+ trees, and hashing techniques.
  4. Query Processing & Optimization: Execution plans, cost estimation, and indexing strategies.
  5. Transaction Management: ACID properties, concurrency control (locks, timestamps), and recovery techniques (log-based, checkpoints).

DBMS Question Paper-GATE & PSU Exam

Q. ___________ is holding an entry for each terminal symbol and is acting as a permanent database.

  1. Variable Table
  2. Terminal Table
  3. Keyword Table
  4. Identifier Table
Answer

Terminal Table
NIELIT 2018

Q. Assume transaction A holds a shared lock R. If transaction B also requests for a shared lock on R. It will

  1. result in a deadlock situation
  2. immediately be granted
  3. immediately be rejected
  4. be granted as soon as it is released by A
Answer

immediately be granted
NIELIT 2017 OCT Scientific Assistant A (CS)

Q. Which one of the following is a key factor for preferring B-trees to binary search trees for indexing database relations?

  1. Database relations have a large number of records
  2. Database relations are sorted on the primary key
  3. B-trees require less memory than binary search trees
  4. Data transfer from disks is in blocks
Answer

Data transfer from disks is in blocks
NIELIT 2017 July Scientist B (CS)

Q. Which of the following is TRUE?

  1. Every relation in 3NF is also in BCNF
  2. A relation R is in 3NF if every non-prime attribute of R is fully functionally dependent on every key of R
  3. Every relation in BCNF is also in 3NF
  4. No relation can be in both BCNF and 3NF.
Answer

Every relation in BCNF is also in 3NF
NIELIT 2017 DEC Scientist B

Q. Consider the relational schema R(A B C D) with following functional dependency set F={A→BC, C→D}; The relation is in

  1. 2NF
  2. BCNF
  3. 3NF
  4. 1NF
Answer

2NF
NIELIT 2017 DEC Scientist B

Q. Which one of the following statements about normal forms is FALSE?

  1. BCNF is stricter than 5NF.
  2. Lossless, dependency-preserving decomposition into BCNF is always possible.
  3. Lossless, dependency-preserving decomposition into 5NF is always possible.
  4. Any relation with two attributes is BCNF.
Answer

Any relation with two attributes is BCNF.
NIELIT 2016 DEC Scientist B (IT)

Q. Given the relations:
employee (name, salary, deptno) and department (deptno, deptname, address). Which of the following queries cannot be expressed using the basic relational algebra operations (U,-,x, , ,P)?

  1. Department address of every employee
  2. Employees whose name is the same as their department name
  3. The sum of all employee’s salaries
  4. All employees of a given department
Answer

The sum of all employee’s salaries
NIELIT 2022 April Scientist B

Q. In an ER Diagram, a double ellipse is used to represent :

  1. Simple Attribute
  2. Composite Attribute
  3. Descriptive Attribute
  4. Multi-valued Attribute
Answer

Multi-valued Attribute
NIELIT 2021 Dec Scientist A

Q. Which one of the following statements is not correct?
S1: NF decomposition is always lossless join and dependency preserving.
S2: NF decomposition is always lossless join but may or may not be dependency preserving.
S3: BCNF decomposition is always lossless join and dependency preserving.
S4: BCNF decomposition is always lossless join but may or may not be dependency preserving.

  1. Only S1
  2. Only S4
  3. Both S1 and S4
  4. Both S2 and S3
Answer

Both S2 and S3
NIELIT 2017 DEC Scientist B

Q. Let R(A, B, C, D) be a relational schema with the following functional dependencies:
A→B, B→C, C→D and D→B
The decomposition of R into (A,B),(B,C),(B,D)

  1. gives a lossless join, and is dependency-preserving
  2. gives a lossless join, but is not dependency-preserving
  3. does not give a lossless join, but is dependency-preserving
  4. does not give a lossless join and is not dependency-preserving
Answer

gives a lossless join, and is dependency preserving
NIELIT 2022 April Scientist B

Q. Indicate which representation is the logical design of the database, and which is a snapshot of the data in the database at a given instant in time.

  1. Instance, Range
  2. Relation, Schema
  3. Relation, Domain
  4. Schema, Instance
Answer

Schema, Instance
NIELIT 2021 Dec Scientist B

Q. In E-R diagrams roles are indicated by labelling the lines that connect which two shapes:

  1. Diamond, Diamond
  2. Rectangle, Circle
  3. Rectangle, Rectangle
  4. Diamond, Rectangle
Answer

Diamond, Rectangle
NIELIT 2021 Dec Scientist B

Q. An attribute(s) that is used to look up records in a file is called a:

  1. Function key
  2. Catalog key
  3. Access key
  4. Search Key
Answer

Search key
NIELIT Scientist B 2020 November

Q. The relation scheme Student Performance (name, couseNo, rollNo, grade) has the following functional dependencies:
• name, courseNo → grade
• rollNo, courseNo → grade
• name → rollNo
• rollNo → name
The highest normal form of this relation scheme is

  1. 2NF
  2. 3NF
  3. BCNF
  4. 4NF
Answer

BCNF
NIELIT 2022 April Scientist B

Q. Which of the following is not a JDBC connection isolation level?

  1. TRANSACTION_NONE
  2. TRANSACTION_READ_COMMITTED
  3. TRANSACTION_REPEATABLE_READ
  4. TRANSACTION_NONREPEATABLE_READ
Answer

TRANSACTION_NONREPEATABLE_READ
NIELIT 2021 Dec Scientist B

Q. Consider a statement

Course (course_id, sec_id, semester)

Here the course_id, sec_id, and semester will be termed as ___________ and Course is a __________ .

  1. Relations, Attribute
  2. Attributes, Relation
  3. Tuple, Relation
  4. Tuple, Attribute
Answer

Attributes, Relation
NIELIT 2021 Dec Scientist B

Q. The number of entity types participating in E-R diagrams is represented by :

  1. Degree of relationship
  2. Structure of relationship
  3. Instance of relationship
  4. Role of relationship
Answer

Degree of relationship
NIELIT 2021 Dec Scientist B

Q. Which of the following scenarios may lead to an irrecoverable error in a database system?

  1. A transaction writes a data item after it is read by an uncommitted transaction
  2. A transaction reads a data item after it is read by an uncommitted transaction
  3. A transaction reads a data item after it is written by a committed transaction
  4. A transaction reads a data item after it is written by an uncommitted transaction
Answer

A transaction reads a data item after it is written by an uncommitted transaction
NIELIT 2022 April Scientist B

Q. Identify the true statement from the given statements:
1. The number of child pointers in a B/B+ tree node is always equal to the number of keys in it plus one
2. The B/B+ tree is defined by the term minimum degree. And minimum degree depends on the hard disk block size, key, and address size

  1. (1)
  2. (1) and (2)
  3. (2)
  4. None of these
Answer

(1) and (2)
NIELIT 2018

Q. If there is more than one key for relation schema in DBMS then each key in relation schema is classified as

  1. prime key
  2. super key
  3. candidate key
  4. primary key
Answer

candidate key
NIELIT 2016 DEC Scientist B (CS)

Q. The primary key is selected from the:

  1. Composite keys
  2. Determinants
  3. Candidate keys
  4. Foreign keys
Answer

Candidate keys
NIELIT 2016 DEC Scientist B (IT)

Q. Let R=(A, B, C, D, W, F) be a relation scheme with the following dependencies: C→F E→a, EC→D, A→1.
Which of the following is a key for R?

  1. CD
  2. EC
  3. AE
  4. AC
Answer

EC
NIELIT 2016 MAR Scientist B

Q. DELETE [FROM] table [WHERE condition]; from the syntax if you omit the WHERE clause.

  1. All rows in the table are deleted.
  2. It will give you an error.
  3. No rows will be deleted.
  4. Only one row will be deleted.
Answer

All rows in the table are deleted.
NIELIT 2021 Dec Scientist B

Q. Point out the wrong statement :

  1. Non-relational databases require that schemas be defined before you can add data
  2. No SQL databases are built to allow the insertion of data without a predefined schema
  3. New SQL databases are built to allow the insertion of data without a predefined schema
  4. All of the options
Answer

New SQL databases are built to allow the insertion of data without a predefined schema
NIELIT Scientist B 2020 November

Q. Let R=(A, B, C, D, E) having the following FDs. F={A→BC, CD→E, B→D, E→A}. Which of the following is not a Candidate key?

  1. A
  2. B
  3. E
  4. BC
Answer

B
NIELIT Scientific Assistant A 2020 November

  1. Structural key
  2. String key
  3. Partial key
  4. Foreign key
Answer

Partial key
NIELIT Scientist B 2020 November

Q. The 2-3-4 tree is a self-balancing data structure, which is also called

  1. 2-4 tree
  2. B+ tree
  3. B- tree
  4. None of the options
Answer

2-4 tree
NIELIT 2017 DEC Scientific Assistant A

Q. An instance of relational schema R(A, B, C) has distinct values of A including NULL values. Which one of the following is true?

  1. A is a candidate’s key
  2. A is not a candidate key
  3. A is a primary key
  4. Both “A is a candidate key” and “A is a primary key”
Answer

A is not a candidate key
NIELIT Scientist B 2020 November

Q. Most NoSQL databases support automatic ___________ meaning that you get high availability and disaster

  1. Processing
  2. Scalability
  3. Replication
  4. All of the options
Answer

Replication
NIELIT Scientist B 2020 November

Q. A minimal super key (i.e, one of the super keys for which no proper subset is a superkey) is called:

  1. Super Key
  2. Candidate Key
  3. Primary Key
  4. Both Candidate and Primary Key
Answer

Candidate Key
NIELIT Scientific Assistant A 2020 November

Q. The employee information in a company is stored in the relation
Employee (name, sex, salary, deptName)
Consider the following SQL query

Select deptName
From Employee
Where sex = ‘M’ Group by deptName
Having avg(salary) >
(select avg (salary) from Employee)

It returns the names of the departments in which

  1. the average salary is more than the average salary in the company
  2. the average salary of male employees is more than the average salary of all male employees in the company
  3. the average salary of male employees is more than the average salary of employees in same the department
  4. the average salary of male employees is more than the average salary in the company
Answer

the average salary of male employees is more than the average salary in the company
NIELIT 2022 April Scientist B

Q. Given the following schema:
employees (emp-id, first-name, last-name, hire-date, dept-id, salary
departments (dept-id, dept-name, manager-id, location-id)
You want to display the last names and hire dates of all the latest hires in their respective departments in the location ID 1700. You issue the following query:

SQL>SELECT last-name, hire-date
FROM employees
WHERE (dept-id, hire-date) IN
(SELECT dept-id, MAX(hire-date)
FROM employees JOIN departments USING(dept-id)
WHERE location-id =1700
GROUP BY dept-id);

What is the outcome?

  1. It executes but does not give the correct result
  2. It executes and gives the correct result.
  3. It generates an error because of pairwise comparison.
  4. It generates an error because of the GROUP BY clause cannot be used with table joins in a sub-query.
Answer

It executes and gives the correct result.
NIELIT 2022 April Scientist B

Q. Given the following relation instance:
Which of the following functional dependencies are satisfied by the instance?

XYZ
142
153
163
322
  1. XY→Z and Z→Y
  2. YZ→X and Y→Z
  3. YZ→X and X→Z
  4. XZ→Y and Y→X
Answer

YZ→X and Y→Z
NIELIT 2016 MAR Scientist C

Q. Consider the schema R=(S T U V) and the dependencies S→T, T→U, U→V and V→S. If R=(R1 AND R2) be a decomposition such that R1∩R2=Φ, then decomposition is

  1. not in 2NF
  2. in 2NF but not in 3NF
  3. in 3NF but not in 2NF
  4. in both 2NF and 3NF
Answer

in both 2NF and 3NF
NIELIT 2016 MAR Scientist C

Q. Consider the following functional dependencies in a database:
A→B
B→C
D→E
E→D
F→G
F→H
(E, F)→I
The relation (E, D, A, B) is

  1. 2NF
  2. 3NF
  3. BCNF
  4. None of the above
Answer

None of the above
NIELIT 2018

Q. The process of analyzing relation schemas to achieve minimal redundancy and insertion or update anomalies is classified as:

  1. normalization of data.
  2. denomination of data.
  3. isolation of data.
  4. de-normalization of data.
Answer

normalization of data.
NIELIT 2016 DEC Scientist B (CS)

Q. Rule which states that the addition of the same attributes to the right side and the left side will result in other valid dependencies is classified as

  1. referential rule
  2. inferential rule
  3. augmentation rule
  4. reflexive rule
Answer

augmentation rule
NIELIT 2016 DEC Scientist B (CS)

Q. If every functional dependency in set E is also in closure of F, then this is classified as

  1. FD is covered by E
  2. E is covered by F
  3. F is covered by E
  4. F plus is covered by E
Answer

E is covered by F
NIELIT 2016 DEC Scientist B (CS)

Q. An instance of relational schema R (A, B, C) has distinct values of A including NULL values. Which one of the following is true?

  1. A is a candidate’s key
  2. A is not a candidate key
  3. A is a primary key
  4. Both 1 and 3
Answer

A is not a candidate key
NIELIT 2021 Dec Scientist A

Q. Consider the relations :
R1 {Roll_no, Name, Grades} and R2 {Roll_no, Subject_ID, Grades}
Which of the following operations cannot be performed using the above relations?

  1. Union
  2. Select
  3. Join
  4. Project
Answer

Union
NIELIT 2021 Dec Scientist A

Q. Consider the following statements :
I. The primary key of a relation cannot contain null values.
II. Unique Key can have null values.
Which among the following is true?

  1. Both I and II are true
  2. Both I and II are false
  3. Only I is true
  4. Only II is true
Answer

Both I and II are true
NIELIT 2021 Dec Scientist A

Q. Considering relational database, the functional dependency between two attributes A and B is denoted by

  1. A→B
  2. C←A
  3. AB→R
  4. R←AB
Answer

A→B
NIELIT 2016 DEC Scientist B (CS)

Q. Assume that a DBA issued the following create table command :
create table A (Aid,…..)
storage (initial 20480, next 20480, maxextents 8, minextents 3, pctincrease 0):
How many bytes of disk space will be allocated to this file when it is first created?

  1. 163,840 bytes
  2. 20480 bytes
  3. 61,440 bytes
  4. 8 bytes
Answer

61,440 bytes
NIELIT 2021 Dec Scientist B

Q. Normalization form which is based on transitive dependency is classified as:

  1. First normal form.
  2. Second normal form.
  3. Fourth normal form.
  4. Third normal form.
Answer

Third normal form.
NIELIT 2016 DEC Scientist B (IT)

Q. In functional dependency between two sets of attributes A and B, then the set of attributes A of the database is classified as:

  1. top right side
  2. down left side
  3. left-hand side
  4. right hand side
Answer

left hand side
NIELIT 2016 DEC Scientist B (IT)

Q. If an attribute of relation schema R is a member of some candidate key then this type of attribute are classified as:

  1. atomic attribute
  2. candidate attribute
  3. non-prime attribute
  4. prime attribute
Answer

prime attribute
NIELIT 2016 DEC Scientist B (IT)

Q. A Young tableau is a 2D array of integers increasing from left to right and from top to bottom. Any unfilled entries are marked with ∞, and hence there cannot be any entry to the right of, or below a ∞. The following Young tableau consists of unique entries.

12514
34623
10121825
31∞∞∞

When an element is removed from a Young tableau, other elements should be moved into its place so that the resulting table is still a Young tableau (unfilled entries may be filled with a ∞). The minimum number of entries (other than 1) to be shifted, to remove 1 from the given Young tableau is __________ .

  1. 2
  2. 5
  3. 6
  4. 18
Answer

6
NIELIT 2022 April Scientist B

Q. For a database relation R(a,b,c,d) where the domains of a,b,c,d include only atomic values, only the following functional dependencies and those that can be inferred from them hold:
a→c
b→d
the relation is in

  1. first normal form but not in the second normal form.
  2. second normal form but not in the third normal form.
  3. third normal form.
  4. none of these.
Answer

first normal form but not in second normal form.
NIELIT 2016 MAR Scientist B

Q. Consider the relational schema R(ABCD) with the following FD set F={A→CE, B→D, AE→D}. Identify the highest normal form satisfied by the relation R.

  1. 2NF
  2. BCNF
  3. 3NF
  4. 1NF
Answer

1NF
NIELIT 2017 DEC Scientist B

Q. Anomalies are avoided by splitting the offending relation into multiple relations, is also known as __.

  1. Acupressure
  2. Decomposition
  3. Precomposition
  4. Both decomposition & composition
Answer

Decomposition
NIELIT Scientific Assistant A 2020 November

Q. Every Boyce-Codd Normal Form (BCNF) decomposition is

  1. dependency preserving
  2. not dependency preserving
  3. need be dependency-preserving
  4. none of these
Answer

none of these
NIELIT 2016 MAR Scientist C

Q. Identify the true statement from the given statements.
1. Lossless, dependency-preserving Decomposition into 3NF is always possible
2. Any relation with two attributes is BCNF

  1. 1
  2. 2
  3. 1 and 2
  4. None of these
Answer

1 and 2
NIELIT 2018

Q. A table joined with itself is called

  1. Join
  2. Self Join
  3. Outer Join
  4. Equi Join
Answer

Self Join
NIELIT 2017 July Scientist B (IT)

Q. Global locks

  1. synchronize access to local resources.
  2. synchronize access to global resources.
  3. are used to avoid local locks.
  4. prevent access to global resources.
Answer

synchronize access to global resources.
NIELIT 2016 MAR Scientist B

Q. If an SQL query involves NOT, AND, OR with no parenthesis

  1. NOT will be evaluated first; AND will be evaluated second; OR will be evaluated last.
  2. NOT will be evaluated first; OR will be evaluated second; AND will be evaluated last.
  3. AND will be evaluated first; OR will be evaluated second ;NOT will be evaluated last.
  4. The order of occurrence determines the order of evaluation.
Answer

NOT will be evaluated first; AND will be evaluated second; OR will be evaluated last.
NIELIT 2017 July Scientist B (IT)

Q. The following table has two attributes X and Y, where X is the primary key and Y is the foreign key referencing X with on-delete cascade.
The set of all tuples that must be additionally deleted to preserve referential integrity when the tuple is (3,4) deleted is

XY
24
34
43
52
72
95
64
  1. (4,3) and (6,4)
  2. (2,4) and (7,2)
  3. (3,2) and (9,5)
  4. (3,4), (4,5) and (6,4)
Answer

(3,4), (4,5) and (6,4)
NIELIT 2018

Q. Domain constraints, functional dependency, and referential integrity are special forms of _______________.

  1. Foreign key
  2. Primary key
  3. Assertion
  4. Referential constraint
Answer

Assertion
NIELIT Scientific Assistant A 2020 November

Q. Which of the following is a fundamental operation in relational algebra?

  1. Set intersection
  2. Assignment
  3. Natural Join
  4. None of the above
Answer

None of the above
NIELIT 2016 DEC Scientist B (IT)

Q. Cross Product is

  1. Unary Operator
  2. Ternary Operator
  3. Binary Operator
  4. Not an operator
Answer

Binary Operator
NIELIT 2017 July Scientist B (IT)

Q. Which of the following desired features are beyond the capability of relational algebra?

  1. Aggregate Computation
  2. Multiplication
  3. Finding transitive closure
  4. All of the above
Answer

All of the above
NIELIT 2017 OCT Scientific Assistant A (IT)

Q. What is meant by the following relational algebra statement: STUDENT×COURSE?

  1. Compute the natural join between the STUDENT and COURSE relations
  2. Compute the left outer join between the STUDENT and CROSS relations
  3. Compute the cartesian product between the STUDENT and CROSS relations
  4. Compute the outer join between the STUDENT and CROSS relations
Answer

Compute the cartesian product between the STUDENT and CROSS relations
NIELIT Scientific Assistant A 2020 November

Q. The relational algebra expression equivalent to the tuple calculus expression is
{t | tЄr Λ (t[A]=10 Λ t[B]=20)} is

  1. σ(A=10 V B=20)(r)
  2. σ(A=10)(r) Ս σ(B=20)(r)
  3. σ(A=10)(r) ∩ σ(B=20)(r)
  4. σ(A=10)(r) – σ(B=20)(r)
Answer

σ(A=10)(r) ∩ σ(B=20)(r)
NIELIT 2016 MAR Scientist B

Q. If R is a relation in the Relational Data Model and A1, A2,….An are the attributes of relation R, what is the cardinality of R expressed in terms of the domain of attributes?

  1. |R| ≤ |dom(A1)×dom(A2)…dom(An)|
  2. |R| ≥ |dom(A1)×dom(A2)…dom(An)|
  3. |R|=max(|dom(A1)|,|dom(A2)|,…|dom(An)|
  4. |R|=min(|dom(A1)|,|dom(A2)|,…|dom(An)|
Answer

|R| ≤ |dom(A1)×dom(A2)…dom(An)|
NIELIT 2017 July Scientist B (IT)

Q. The employee salary should not be greater than Rs.2000. This is

  1. integrity constraint
  2. referential constraint
  3. over-defined constraint
  4. feasible constraint
Answer

integrity constraint
NIELIT 2016 MAR Scientist B

Q. A primary key, if combined with a foreign key creates

  1. parent-child relationship between the tables that connect them
  2. many-to-many relationship between the tables that connect them
  3. network model between the tables that connect them
  4. none of these
Answer

parent child relationship between the tables that connect them
NIELIT 2016 MAR Scientist C

Q. The condition for total participation of an entity in a relationship is ______________ .

  1. Maximum cardinality should be one
  2. Minimum cardinality should be one
  3. Minimum cardinality should be zero
  4. None of the options
Answer

Minimum cardinality should be one
NIELIT 2017 DEC Scientist B

  1. data file
  2. data record
  3. menu
  4. bank
Answer

data record
NIELIT 2017 July Scientist B (IT)

Q. What is the modality of a relationship, if there is no explicit need for a relationship to occur?

  1. Zero
  2. Two
  3. Three
  4. One
Answer

Zero
NIELIT 2017 OCT Scientific Assistant A (CS)

Q. ______ symbol is used to denote derived attributes in ER model

  1. Dashed ellipse
  2. Squared ellipse
  3. Ellipse with attribute name underlined
  4. Rectangular Box
Answer

Dashed ellipse
NIELIT 2018

Q. Consider the following four schedules due to three transactions (indicated by the subscript) using read and write on a data item x, denoted by r(x) and w(x) respectively. Which one of them is conflict serializable?
1. r1(x);r2(x);w1(x);r3(x);w2(x)
2. r2(x);r1(x);w2(x);r3(x);w1(x)
3. r3(x);r2(x);r1(x);w2(x);w1(x)
4. r2(x);w2(x);r3(x);r1(x);w1(x)

  1. 1
  2. 2
  3. 3
  4. 4
Answer

4
NIELIT 2017 July Scientist B (CS)

Q. Which type of Statement can execute parameterized queries?

  1. PreparedStatement
  2. ParameterizedStatement
  3. ParameterizedStatement and CallableStatement
  4. All kinds of Statements
Answer

PreparedStatement
NIELIT 2016 DEC Scientist B (IT)

Q. ‘AS’ clause is used in SQL for

  1. Selection operation
  2. Rename operation
  3. Join Operation
  4. Projection Operation
Answer

Rename operation
NIELIT 2017 July Scientist B (IT)

Q. Given relations R(w,x) and S(y,z), the result of

SELECT DISTINCT w,x from R,S
  1. R has no duplicates and S is non-empty
  2. R and S have no duplicates
  3. S has no duplicates and R is non-empty
  4. R and S have the same number of tuples
Answer

R has no duplicates and S is non empty
NIELIT 2017 OCT Scientific Assistant A (CS)

Q. Table employees has 10 records. It has a non-NULL SALARY column which is also UNIQUE. The SQL statement

SELECT COUNT(*)
FROM EMPLOYEE
WHERE SALARY > ALL (SELECT SALARY FROM EMPLOYEE);
  1. 10
  2. 9
  3. 5
  4. 0
Answer

0
NIELIT 2017 OCT Scientific Assistant A (CS)

Q. (<ALL) comparison operator means:

  1. more than the maximum value in the subquery
  2. less than the minimum value in the subquery
  3. is equivalent to IN
  4. none of the options
Answer

less than the minimum value in the subquery
NIELIT Scientific Assistant A 2020 November

Q. With the following syntax

INSERT INTO table[(column[, column…]) ] 
VALUES (value[, value…]);

you can:

  1. Insert one row at a time
  2. Insert multiple rows at a time
  3. Insert one column at a time
  4. Insert multiple columns at a time
Answer

Insert one row at a time
NIELIT Scientific Assistant A 2020 November

Q. When retrieving data in a particular table in PostgreSQL, we use the ___________ statement.

  1. \dt
  2. ORDER BY
  3. SELECT FROM
  4. \i
Answer

SELECT FROM
NIELIT Scientific Assistant A 2020 November

Q. Maximum number of superkeys for the relation schema R(X, Y, Z, W) with X as the key is

  1. 6
  2. 8
  3. 9
  4. 12
Answer

8
NIELIT 2018

Q. 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

  1. Wait-die
  2. Wait-wound
  3. Wound-wait
  4. Wait
Answer

Wait-die
NIELIT 2017 OCT Scientific Assistant A (CS)

Q. Which of the following scenarios may lead to an irrecoverable error in a database system?

  1. A transaction writes a data item after it is read by an uncommitted transaction
  2. A transaction reads a data item after it is read by an uncommitted transaction
  3. A transaction reads a data item after it is written by a committed transaction
  4. A transaction reads a data item after it is written by an uncommitted transaction
Answer

A transaction reads a data item after it is written by an uncommitted transaction
NIELIT Scientific Assistant A 2020 November

Q. ___________ is NOT a part of the ACID properties

  1. Inconsistency
  2. Consistency
  3. Atomicity
  4. Isolation
Answer

Inconsistency
NIELIT 2018

Q. In a relational Schema, each tuple is divided into fields called

  1. relations
  2. domains
  3. queries
  4. none of these
Answer

domains
NIELIT 2016 MAR Scientist B

Q. Consider the join of a relation R with relation S. If R has m tuples and s has n tuples, then the maximum size of the join is

  1. mn
  2. m+n
  3. (m+n)/2
  4. 2(m+n)
Answer

mn
NIELIT 2017 July Scientist B (IT)

Q. In tuple relational calculus P1→P2 is equivalent to

  1. ¬P1 V P2
  2. P1 V P2
  3. P1 Λ P2
  4. P1 Λ ¬P2
Answer

¬P1 V P2
NIELIT 2017 July Scientist B (IT)

Q. E-R model uses this symbol to represent a weak entity set.

  1. Dotted rectangle
  2. Diamond
  3. Doubly outlined rectangle
  4. None of these
Answer

Doubly outlined rectangle
NIELIT 2017 OCT Scientific Assistant A (CS)

Q. In conservative two-phase locking protocol, a transaction

  1. Should release all the locks only at the beginning of the transaction
  2. Should release exclusive locks only after the commit operation
  3. Should acquire all the exclusive locks at the beginning of the transaction
  4. Should acquire all the locks at the beginning of the transaction
Answer

Should acquire all the locks at the beginning of transaction
NIELIT 2017 DEC Scientist B

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