Information Technology · Class 11 Commerce

Ch 3Relational Database Management System — Class 11 Information Technology, concept-first.

Every business and every office runs on facts. The name of a customer, the price of a product, the quantity sold on a particular date, the roll number of a student, or the balance in a bank account — all of these are examples of data.

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Key concepts

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Data, Information and Database

Data are raw facts and figures; when data is processed and organised so that it becomes meaningful for decisions, it becomes information.

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Distinguish between data and information, giving one example of each.Free

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Chapter contents

The NCERT structure, section by section. Open a section to see its questions, then read the concept-first solution.

Data, Information and the Need for a Database

DBMS and RDBMS

A Database Management System (DBMS) is software that lets users create, store, organise, retrieve, update and manage the data in a database.

The Relational Model — Relations, Tuples and Attributes

A database model describes the logical structure of a database — how the data is organised and how different pieces of data relate to one another.

Data Types in MySQL

When a table is created, each attribute (column) is given a data type that decides what kind of value it can hold and how much space it takes.

Keys in a Relational Database

A key is an attribute (or a combination of attributes) used to identify tuples in a relation and to link relations together.

Introduction to MySQL and SQL

MySQL is a popular, open-source Relational Database Management System. Being open-source means it is free to download and use, which is one reason it is widely used both for learning and in real websi…

DDL — Creating and Using a Database and Tables

Before storing any data, we must first create a database to hold our tables, then create the tables themselves. These jobs are done with DDL commands.

DML — Inserting, Updating and Deleting Data

Once a table exists, DML commands are used to put data into it, change it and remove it.

Selecting and Filtering Data — SELECT, WHERE and Operators

The SELECT statement is used to read data back from a table, and it is the command used most often. To see every column of every row, use the symbol, which means 'all columns':

Exercises

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