Class notes DBMS

University-Level Database Management System (DBMS) Course PDF




1. Introduction to DBMS
Definition: Database Management System (DBMS) is software that manages data, databases, and provides
users with the tools to store, manipulate, and retrieve data efficiently.


Types of DBMS: - Hierarchical DBMS - Network DBMS - Relational DBMS (RDBMS) - NoSQL DBMS


Advantages: - Reduced data redundancy - Data consistency - Data security - Multiple user access - Easy
data retrieval




2. Database Models
ER Model: - Entities: Real-world objects (Student, Course) - Attributes: Properties of entities (StudentName,
RollNo) - Relationships: Links between entities (Enrolls)


ER Diagram Example:



Student --< Enrolls >-- Course



ER to Table Conversion: - Entity becomes table - Attributes become columns - Relationships mapped via
foreign keys




3. Relational Model
Tables: Rows (tuples), Columns (attributes)


Keys: - Primary Key (PK) : Unique identifier - Foreign Key (FK) : Links tables


Relationships: - 1:1, 1:M, M:N




4. SQL Basics
Database Creation:




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, CREATE DATABASE UniversityDB;
USE UniversityDB;



Table Creation:



CREATE TABLE Student (
RollNo INT PRIMARY KEY,
StudentName VARCHAR(50),
Age INT
);



Insert Data:



INSERT INTO Student VALUES (1, 'Alice', 20);
INSERT INTO Student VALUES (2, 'Bob', 21);



Select Data:



SELECT * FROM Student;
SELECT StudentName FROM Student WHERE Age > 20;



Update Data:



UPDATE Student SET Age = 22 WHERE RollNo = 2;



Delete Data:



DELETE FROM Student WHERE RollNo = 1;




5. Advanced SQL
JOINs:



-- INNER JOIN
SELECT Student.StudentName, Course.CourseName




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