DBMS and SQL Basics for Class 10 Information Technology

Database Management System

Class 10 - Information Technology

Data vs. Information

Data: Raw, unorganized facts and figures (e.g., '25', 'Rohan').

Information: Processed data that has meaning (e.g., 'Rohan is 25 years old').

What is a DBMS?

A Database Management System (DBMS) is software used to store, manage, and retrieve data efficiently.

Popular Examples: MySQL, Oracle, PostgreSQL, Microsoft Access.

Why use a DBMS?

Reduces Data Redundancy: Prevents duplicate data.

Data Consistency: Ensures data matches across the system.

Data Security: Restricts unauthorized access.

Data Sharing: Multiple users can access data at once.

Database Structure: The Table

Table (Relation): The container holding data.

Field (Column): A specific category of information (e.g., Name).

Record (Row): Information about one specific item (e.g., one student).

The Primary Key

A Primary Key is a field that uniquely identifies each record in a table.

• Values must be unique. • Cannot differ or contain NULL values. • Example: Admission Number, Roll Number.

The Foreign Key

A Foreign Key is a field that links one table to the Primary Key of another table.

It creates a relationship between two tables, ensuring data integrity.

RDBMS

Relational Database Management System

Data is stored in tables (relations) which are linked to each other using common fields. This is the most common type of database today.

Introduction to SQL

SQL (Structured Query Language) is the standard language used to communicate with an RDBMS.

It allows us to create databases, manipulate data, and retrieve specific information.

Most Popular SQL Databases (Dev Survey 2023)

Learning MySQL (Open Source) prepares you for the most widely used technologies.

SQL Command Categories

DDL (Data Definition)

• CREATE (New table) • ALTER (Modify structure) • DROP (Delete table)

DML (Data Manipulation)

• INSERT (Add data) • UPDATE (Change data) • DELETE (Remove data) • SELECT (View data)

Common Data Types

Every field must have a type to define what data it holds.

INTEGER / INT: Whole numbers (e.g., 10, 500).

CHAR / VARCHAR: Text and numbers (e.g., 'Apple', 'A-12').

DATE: Dates only (e.g., '2023-11-25').

Summary

DBMS software manages data efficiently compared to files.

Data is stored in Tables using Rows and Columns.

Primary Keys ensure uniqueness; Foreign Keys link tables.

SQL is the language used to command the database.