DBMS for Class 10 IT (Code 402) - Database Fundamentals

Database Management System

Class 10 IT (Code 402) - Unit 3

Data vs. Information

Before understanding DBMS, we must distinguish between Data and Information. Data consists of raw, unorganized facts and figures (e.g., '10', 'Rahul'). Information is processed data that has meaning and context (e.g., 'Rahul is in Class 10').

What is a DBMS?

A Database Management System (DBMS) is a software package designed to define, manipulate, retrieve, and manage data in a database. It acts as an interface between the data and the user applications. Examples include MySQL, Oracle, and Microsoft Access.

Popular Databases by Documented Usage

In the professional IT world, different DBMS software is used based on requirements. Here is a breakdown of popular databases predominantly used by developers in 2023-2024.

Why use a DBMS?

Reduces Data Redundancy: Prevents duplicate data entry across files.

Controls Data Inconsistency: Ensures data matches across all views.

Facilitates Data Sharing: Multiple users can access data simultaneously.

Ensures Data Security: Restricts unauthorized access.

Relational Data Model (RDBMS)

RDBMS stands for Relational Database Management System. It stores data in the form of 'Relations' (commonly known as Tables). This is the most popular type of database model used today (e.g., MySQL, OpenOffice Base).

Database Components

A database comprises several key components:<br><br><b>Table:</b> Organized set of data elements.<br><b>Record (Tuple):</b> A single row of data.<br><b>Field (Attribute):</b> A column describing a characteristic.

Primary Key

A Primary Key is a unique field that identifies each record in a table. <br><br>• It must contain unique values.<br>• It cannot contain NULL values.<br>• Examples: Roll Number, Admission Number, Employee ID.

Foreign Key

A Foreign Key is a field (or collection of fields) in one table that refers to the Primary Key in another table. It acts as a cross-reference between the two tables, establishing a relationship between them.

Common Data Types

NUMERIC: Stores numbers (Integer, Decimal, Float).

ALPHANUMERIC: Stores text (CHAR for fixed length, VARCHAR for variable length).

BINARY: Stores images or sounds (BLOB - Binary Large Object).

DATE/TIME: Stores calendar dates and time stamps.

SQL (Structured Query Language) is the standard language for dealing with Relational Databases.

Essential Knowledge

DDL Commands

Data Definition Language (DDL) is used to define the database structure/schema.<br><br><b>CREATE:</b> Creates a new table or database.<br><b>ALTER:</b> Modifies an existing database structure.<br><b>DROP:</b> Deletes a table or database.

DML Commands

Data Manipulation Language (DML) is used for accessing and manipulating data.<br><br><b>INSERT:</b> Insert new data.<br><b>UPDATE:</b> Modify existing data.<br><b>DELETE:</b> Remove data.<br><b>SELECT:</b> Retrieve data.

Database Objects: Forms

A Form provides a user-friendly interface that lets users enter or modify data in a database without interacting directly with the tables. It acts as a window to the data.

Database Objects: Reports

A Report is used to display the data in a formatted, printable manner. Reports are typically used to summarize and present data (e.g., generating a monthly sales summary or a report card).

Defining Relationships

One-to-One: Both tables can have only one record on either side of the relationship (e.g., Person to Passport ID).

One-to-Many: One record in the primary table is linked to multiple records in the related table (e.g., Class Teacher to Students).

Many-to-Many: Multiple records in one table valid for multiple records in another (e.g., Students to Courses).

Thank You!