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Data Base Management System Nptel Assignment 1 Answers
Data Base Management System Nptel Assignment 1 Answers (July-Dec 2025)
Question 1. Which level of abstraction describes how data is physically stored in the database? a) Physical level b) Logical level c) View level d) Abstraction level
Identify the correct statement. a) S1 is a Data Definition (DDL) Query, and S2 is a Data Manipulation (DML) Query. b) Both S1 and S2 are Data Definition (DDL) Queries. c) S1 is a Data Control Query (DCL), and S2 is a Data Definition (DDL) Query. d) Both S1 and S2 are Data Manipulation (DML) Queries.
Question 3. Identify the correct statement(s) about database schemas and instances. a) Student(roll no, name, dept) represents a database instance. b) (101, ‘John’, ‘CS’) is an example of a relation schema. c) Course(course_id, title) defines a logical schema. d) (‘CS101’, ‘Databases’) is an instance of a physical schema.
Question 4. Consider the following international university admissions data:
University
Year
CourseCode
StudentName
Country
Year
University of Delhi
2023
CS101
Riva Sharma
India
2023
ETH Zurich
2022
PH202
Noah Miller
Switzerland
2022
University of Delhi
2023
ME105
Arjun Patel
India
2023
National University of Singapore
2024
EE110
Li Wei
Singapore
2024
ETH Zurich
2023
CS101
Riya Sharma
Switzerland
2023
Identify the valid primary key for the relation university_admissions from the given instance. a) university and country b) student_id and admission_year c) university and student_id d) student name and admission_year
Question 6. Consider the relational schema StudentGrades (StudentID, CourseCode, Grade, Semester). If the following tuple exists in an instance of StudentGrades:
(TT, CS, PN, TE)
Which of the following tuples can NOT be inserted into StudentGrades? a) b) c) d)
Which relational algebra operation extracts only river names and their lengths? a) σ Length > 3000 (RiverDetails) b) π RiverName, Length (RiverDetails) c) RiverDetails × RiverDetails d) RiverDetails ▷ Country = ‘Brazil’ RiverDetails
Que. 1: Which of the following statements is (are) incorrect? a) Logical level abstraction defines the physical storage of data. b) View level abstraction provides a user-friendly interface for end users. c) Physical level abstraction focuses on the relationships among data. d) Logical level abstraction focuses on the relationships among data.
sqlCopyEditINSERT INTO emp_name, dept)
VALUES (101, 'Alice', 'HR');
ALTER TABLE employees ADD count salary number(8, 2);
Identify the correct statement. a) Both S1 and S2 are Data Manipulation (DML) Queries. b) S1 is a Data Manipulation (DML) Query, and S2 is a Data Definition (DDL) Query. c) Both S1 and S2 are Data Definition (DDL) Queries. d) S1 is a Data Control Query, and S2 is a Data Definition (DDL) Query.
Que. 4: Identify the correct statement(s): a) Employee(empID, empName) is an instance of a relation schema. b) Employee(empID, empName) is an example of a physical schema. c) (101, John) is an instance of a relation schema. d) (101, John) is an example of a logical schema.
Que. 5: Consider a relation CityDetails(CityName, Population, CountryName) where the superkeys are as follows: {CityName}, {CityName, Population}, {CityName, CountryName}, {CityName, Population, CountryName}.
Select the possible candidate key(s). a) {CityName, Population, CountryName}. b) {CityName, Population}. c) {CityName}. d) {CityName, CountryName}.
Que. 7: Consider the following instance of the CourseDetails (CourseID, CourseName) relation:
CourseID
CourseName
C101
Mathematics
C102
Physics
If CourseID is the foreign key in the relational schema StudentEnrollments (EnrollmentID, StudentName), which of the following is a valid instance of StudentEnrollments?
These are Data Base Management System Nptel Assignment 1 Answers
Q1. Consider the SQL statement(s) below: S1: CREATE table students( student_id number(5), student_name varchar2(20), address varchar2(20), emailid varchar2(20)); S2: DELETE FROM students WHERE student_id = 10005; Identify the correct statement. a) Both S1 and S2 are Data Definition (DDL) Queries b) Both S1 and S2 are Data Manipulation (DML) Queries c) S1 is a Data Definition (DDL) Query and S2 is a Data Manipulation Query (DML) d) S1 is a Data Control Query and S2 is a Data Manipulation (DML) Query
These are Data Base Management System Nptel Assignment 1 Answers
Q3. Identify the correct statement/s. a) Logical schema defines the overall logical structure of the database. b) Logical schema defines the overall physical structure of the database. c) Physical schema defines the overall logical structure of the database. d) View schema defines the interaction between end-user and database.
Answer: a) Logical schema defines the overall logical structure of the database.
d) View schema defines the interaction between end-user and database.
Q4. Consider a relation MountainDetails (MountainName, Altitude, StateName) where the su- perkeys are as follows: (MountainName}, {MountainName, Altitude}, {MountainName, StateName}, {MountainName, Altitude, StateName). Select the possible candidate key(s). a) {MountainName, Altitude, StateName} b) {MountainName, StateName} c) {MountainName, Altitude} d) {MountainName}
These are Data Base Management System Nptel Assignment 1 Answers
Q5. Let students (student_id, student name, address, emailid) and enrolment (student_id, dept name, enrolment_date) be two relations in a schema. The primary keys are shown underlined. Let student_id be a foreign key in enrolment relation referring to students relation. Suppose, there is no violation of the above referential integrity constraint in the corresponding relation instances of students and enrolment. Which one of the following relational algebra expressions would necessarily produce an empty relation? a) Istudent_id (enrolment) Istudent_id (students) b) Istudent_id (students) Istudent_id (enrolment) c) Istudent_id(enrolment <> students) d) Istudent_id (enrolment students)
Answer: a)
Q6.Which of the following statements is (are) correct? a) View level abstraction describes how a record is stored. b) View level abstraction hides details of data types and focuses on the interaction with the end-users. c) Logical level abstraction describes what data is stored in a database and their relationships. d) Physical level abstraction describes what data is stored in a database and their relationships.
Answer: b) View level abstraction hides details of data types and focuses on the interaction with the end-users. c) Logical level abstraction describes what data is stored in a database and their relationships.
These are Data Base Management System Nptel Assignment 1 Answers
Q7. Consider the following instance of the Student Details (StudentID, Student name) relation:
Answer : d)
Q8. Consider the following tables:
a) ChatDetails ChatDetails b) ChatDetails2 ChatDetailsı c) (ChatDetails ChatDetails₂) U (ChatDetails2 ChatDetails1) d) (ChatDetails₁ U ChatDetails₂) ∩ (ChatDetails ChatDetails2)
