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A database is a collection of information

that's related to a particular subject or

purpose.

What is database ?

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Some Examples

y Telephone directory

y Patients records in a

hospital

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Examples contd.

y Library Catalogy Books Available.

y Members Information.

y Which Books with whom.

y University Class Schedule -

Timetabley Students have many professors.

y

Professors have many students.y Classes can be held in many

classrooms.

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Database Purpose

Store

Sort

Retrieve

DATA

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Without aid ofcomputer

y You're having to coordinate and organize yourself

y If an STD-code number changes, you might have toupdate that information in all places

y

More than 1 person needs to enter data at the same timey You need to give certain people access to one view of the

data and other people to a different view

Contd

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Queryingis difficult

y Select all the people with brown hair, high blood pressure,

and younger than 37

y Match all survey information with voting history for 400,000

peopley Show all the purchases on a given day and add on personal

information for any people where we have the information

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Ifyour database is stored on a

computer

y Any change in a particular data is automatically updated

wherever you use it in the database.

y Querying very easy

ydefine relationships, data types and many more.

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Basic Database Concepts

Table A set of related

records

Name: Ravi

Department: Garden

Tel: 2437766

Name: Ravi

Department: Garden

Tel: 2437766

Name: Ravi

Field

Record

A collection of data

about an individual item

A single item of data

common to all records

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Tables toStore and manage your data

How data is organized in tables?

y A table is a collection of

data about a specific topic.

y Tables organize data intocolumns (called fields) and

rows (called records).

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Data typesData types

yData type for data integrity (field data type: A

characteristic of a field that determines what kindof data it can store.

y Applicable data typesyTextyBytey IntegeryLong IntegerySingleyDoubleyDecimal

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The single table databaseThe single table database

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DefinitionsDefinitions

y A database is a collection of stored operational data used byvarious applications and/or users by some particular enterprise orby a set of outside authorized applications and authorized users

y A DataBase Management System (DBMS) is a software system

that manages execution of users applications to access and modifydatabase data so that the data security, data integrity, and datareliability is guaranteed for each application and each application iswritten with an assumption that it is the only application active inthe database.