MCS-023 Solved Assignment January 2026 | Introduction to Database Management Systems | IGNOU BCA

Q: Consider the following relational schemas for a company database: Employees (EmpID, EmpName, Salary, DeptID) Departments (DeptID, DeptName) Projects (ProjID, ProjName, Lead_EmpID) Write and execute SQL queries for the following tasks. Make suitable assumptions where necessary.

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QQ1. Answer the following questions:

(a)) Differentiate between a File Processing System and a Database Management System (DBMS) based on four key aspects. (300 words)
(b)) Explain the three-level architecture of a DBMS (External, Conceptual, and Internal). How does this architecture support Logical and Physical Data Independence? (300 words)
(c)) What are the ACID properties of a transaction? Explain each property with a suitable example of an airline ticket booking. (300 words)
(d)) Differentiate between DDL (Data Definition Language) and DML (Data Manipulation Language) statements in SQL. Provide two examples for each category. (300 words)
(e)) Explain the difference between 3NF (Third Normal Form) and BCNF (Boyce-Codd Normal Form). Provide an example of a relation that is in 3NF but not in BCNF. (300 words)

Key Points:

DBMS offers better data redundancy, sharing, integrity, and security than File Processing Systems.
DBMS 3-level architecture: External (user view), Conceptual (global logical view), Internal (physical storage).
Data Independence: Logical (conceptual changes don't affect external) and Physical (internal changes don't affect conceptual/external).
ACID properties: Atomicity (all or nothing), Consistency (valid state), Isolation (concurrent transactions don't interfere), Durability (committed changes are permanent).

Answer: This document provides comprehensive answers to five key questions concerning Database Management Systems (DBMS), drawing from typical course content aligned with IGNOU's MCS-023. It differentiates between file processing systems and DBMS, explains the three-level DBMS architecture and data independence, elaborates on ACID properties of transactions with examples, distinguishes DDL and DML in SQL, and clarifies the difference between 3NF and BCNF with a suitable example. Each sub-question is ad...

QQ2. An online learning platform, "EduSphere," needs a database to manage its operations. The requirements are as follows: The platform has many Students. Each student is identified by a unique StudentID and has a Name, Email, and RegistrationDate. The platform features several Instructors. Each instructor has a unique InstructorID, Name, and a short Bio. There are multiple Courses on offer. Each course has a unique CourseID, a Title, Duration (in hours), and a Fee. An instructor can teach multiple courses, but each course is taught by only one instructor. A student can enroll in multiple courses, and a course can have many students. When a student enrolls, the EnrollmentDate and the final Grade obtained are recorded.

(a)) Design a complete ER (Entity-Relationship) diagram for the "EduSphere" platform. Clearly show all entities, attributes (including primary keys), relationships, and their cardinality constraints. (300 words)
(b)) Convert the ER diagram from part (a) into a set of relational schemas (tables). You must underline the primary key for each table and clearly indicate all foreign keys and the tables they reference. (300 words)

Key Points:

ER modeling uses entities, attributes, and relationships to conceptually represent database structure.
Primary keys (e.g., StudentID) uniquely identify each record within an entity or table.
One-to-many (1:N) relationships are implemented by placing the primary key of the 'one' side as a foreign key in the 'many' side's table.
Many-to-many (M:N) relationships require an associative entity (also known as a junction table) for resolution.

Answer: The design of a database for an online learning platform like "EduSphere" begins with a conceptual Entity-Relationship (ER) model, which then translates into a logical set of relational schemas. This two-step process, common in database design as taught in MCS-023, ensures that all functional requirements are captured accurately and efficiently. The ER diagram provides a high-level view of the entities, their attributes, and relationships, while the relational schemas offer a detailed blueprint ...

QQ3. Consider the following relational schemas for a company database: Employees (EmpID, EmpName, Salary, DeptID) Departments (DeptID, DeptName) Projects (ProjID, ProjName, Lead_EmpID) Write and execute SQL queries for the following tasks. Make suitable assumptions where necessary.

(a)) Create the Employees table with EmpID as the primary key and DeptID as a foreign key referencing the Departments table. The Salary should not be negative. (300 words)
(b)) List the names and salaries of all employees working in the 'Technology' department, sorted in descending order of their salary. (300 words)
(c)) Find the name of each department and the number of employees working in it. Display only those departments that have more than 10 employees. (300 words)
(d)) Find the names of all employees whose salary is greater than the average salary of all employees in the company. (300 words)
(e)) List the names of all projects along with the name of the employee who is leading the project. (300 words)

Key Points:

DDL `CREATE TABLE` defines table structure, data types, and constraints (PRIMARY KEY, FOREIGN KEY, CHECK).
DML `SELECT` with `JOIN` combines data from multiple tables based on related columns.
`WHERE` clause filters individual rows, while `HAVING` filters groups after aggregation.
`GROUP BY` is essential with aggregate functions like `COUNT()` to summarize data per group.

Answer:

QQ4. This question has two main parts (a) and (b).

(a)) Consider the relation R(A, B, C, D, E, F) with the following set of Functional Dependencies (FDs): F = { A → BC, CD → E, B → D, E → A } (i) Find all the candidate keys for the relation R. (ii) Is the relation R in 3NF? Justify your answer. (iii) Decompose the relation R into a set of relations that are in BCNF. (300 words)
(b)) Consider the following schedule S with two transactions T1 and T2: S: R1(X); W1(X); R2(X); W2(X); R1(Y); W1(Y); Commit1; R2(Y); W2(Y); Commit2; (i) Draw the precedence (serializability) graph for the schedule S. (ii) Is the schedule S serializable? If yes, provide the equivalent serial schedule(s). If no, explain why. (iii) Identify any concurrency problems (e.g., Lost Update, Dirty Read) present in this schedule. Explain how the problem occurs. (300 words)

Key Points:

Candidate keys are minimal superkeys that uniquely identify tuples in a relation.
3NF requires that for every FD X→A, X is a superkey or A is a prime attribute.
BCNF is stricter than 3NF, requiring that X must be a superkey for every FD X→A.
BCNF decomposition ensures lossless join but may not preserve all functional dependencies.

Answer: The following response addresses the two main parts of the question, covering relational database normalization and concurrency control in database management systems, as per the MCS-023 course curriculum. Part (a) focuses on analyzing a given relation and its functional dependencies to determine candidate keys, assess its 3NF status, and perform BCNF decomposition. This involves applying fundamental concepts of normal forms and dependency theory. Part (b) delves into transaction scheduling, r...

MCS-023 Solved Assignment — January 2026 / July 2025

Introduction to Database Management Systems | IGNOU Bachelor of Computer Applications (BCA)

MCS-023—January 2026 / July 2025

Introduction to Database Management Systems

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MCS-023 Assignment Questions — January 2026

QQ1. Answer the following questions:

QQ3. Consider the following relational schemas for a company database: Employees (EmpID, EmpName, Salary, DeptID) Departments (DeptID, DeptName) Projects (ProjID, ProjName, Lead_EmpID) Write and execute SQL queries for the following tasks. Make suitable assumptions where necessary.

QQ4. This question has two main parts (a) and (b).