CS/IT Gate Subject

Aptitude and Reasoning
Engineering Mathematics
C Programming
Data Structure
Design Algorithm Analysis
Operating System
Computer Network
Digital Logic Design
Compiler Design
Database Management System
Theory of Computation

DBMS GATE CS and IT previous year questions with answer

Ques 1 Gate 2024 Set-1

Let S be the specification: "Instructors teach courses. Students register for courses. Courses are allocated classrooms. Instructors guide students." Which one of the following ER diagrams CORRECTLY represents S?

(i)

(ii)

(iii)

(iv)

Ques 2 Gate 2023

Which one of the option given below refers to the degree of relation in relational database systems?

Number of distinct domains of its relation schema.

Number of attributes of its relation schema.

Number of entries in the relation.

Number of tuples stored in the relation.

Ques 3 Gate 2022

Let Ri(z) and Wi(z) denote read and write operations on a data element z by a transaction Ti, respectively. Consider the schedule S with four transactions.

S: R4(x)R2(x)R3(x)R1(y)W1(y)W2(x)W3(y)R4(y)

Which one of the following serial schedules is conflict equivalent to S?

T₁→T₃→T₄→T₂

T₁→T₄→T₃→T₂

T₄→T₁→T₃→T₂

T₃→T₁→T₄→T₂

Ques 4 Gate 2022

In a relational data model, which one of the following statements is TRUE?

A relation with only two attributes is always in BCNF.

If all attributes of a relation are prime attributes, then the relation is in BCNF.

Every relation has at least one non-prime attribute.

BCNF decompositions preserve functional dependencies.

Ques 5 Gate 2022

Consider the following three relations in a relational database. Employee (eId, Name ), Brand (bId, bName), Own (eId, bId ) Which of the following relational algebra expressions return the set of eIds who own all the brands?

π_eld(π_eld,bld(own)/π_brand))

π_eld(own)-π_eld((π_eld(own)xπ_bld(brand))-π_bld,eld(own))

π_eld(π_eld,bld(own)/π_own))

π_eld((π_eld(own)xπ_bld(own))/π_bld(brand))

Ques 6 Gate 2022

Consider two files systems A and B , that use contiguous allocation and linked allocation, respectively. A file of size 100 blocks is already stored in A and also in B. Now, consider inserting a new block in the middle of the file (between 50th and 51st block), whose data is already available in the memory. Assume that there are enough free blocks at the end of the file and that the file control blocks are already in memory. Let the number of disk accesses required to insert a block in the middle of the file in A and B are n_A and n_B respectively, then the value of n_A + n_B is_________.

153 is the correct answer.

Ques 7 Gate 2020

Consider a relational table R that is in 3NF, but not in BCNF. Which one of the following statements is TRUE ?

R has a nontrivial functional dependency X→A, where X is not a superkey and A is a prime attribute.

R has a nontrivial functional dependency X→A, where X is not a superkey and A is a non-prime attribute and X is not a proper subset of any key.

R has a nontrivial functional dependency X→A, where X is not a superkey and A is a non-prime attribute and X is a proper subset of some key.

A cell in R holds a set instead of an atomic value.

Ques 8 Gate 2020

Which one of the following is used to represent the supporting many-one relationships of a weak entity set in an entity-relationship diagram ?

Diamonds with double/bold border

Rectangles with double/bold border

Ovals with double/bold border

Ovals that contain underlined identifiers

Ques 9 Gate 2019

Consider the following two statements about database transaction schedules:

I. Strict two-phase locking protocol generates conflict serializable schedules that are also recoverable.
II. Timestamp-ordering concurrency control protocol with Thomas’ Write Rule can generate view serializable schedules that are not conflict serializable.

Which of the above statements is/are TRUE?

I only

II only

Both I and II

Neither I nor II

Ques 10 Gate 2019

Let the set of functional dependencies F = {QR → S, R → P, S → Q} hold on a relation schema X = (PQRS). X is not in BCNF. Suppose X is decomposed into two schemas and Z where Y = (PR) and Z = (QRS).
Consider the two statements given below:

I. Both Y and Z are in BCNF
II. Decomposition of X into Y and Z is dependency preserving and a lossless.

Which of the above statements is/are correct?

Both I and II

Neither I nor II

I only

II only