1-Introduction to Database

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Introduction to Datab

Prepared By :

Syed Sarmad Ali



Topics To Be Covered Introduction about Database.

Characteristics of the database approach.

Actors on the scene.

Workers behind the scene.

Introduction to DBMS.

Advantages of using a DBMS.

Implications of the database approach.

When not to use a DBMS.



Structured And Unstructured dat

– Flat file = unstructured data

– Database = structured data

• The Problem with Unstructured Data

High maintenance costs

Data Redundancy: the same data will be represemultiple times in the file.

Data dependence: if you change things about thformat then there will be expensive changes to pruse it.

Ensuring data consistency and controlling accessis difficult (i.e. you cannot finely control multi-user athe file)



Database

Data = facts and figures

Information = processed data.

A database is a collection of data, typically the activities of one or more related organizaexample, a university database might contai

information about the following: Entities such as students, faculty, courses, and

classrooms.



Basic Definition

• Database: A collection of related data.

• Data: Known facts that can be recorded and have meaning.

• Mini-world: Some part of the real world about wstored in a database. For example, student grades

at a university.• Database Management System (DBMS): A s

package/ system to facilitate the creation and maicomputerized database.

• Database System: The DBMS software togetheritself. Sometimes, the applications are also includ



Database System

Application

program

End-user

DBMS



Example of a Database(with a Conceptual Data Mode

Mini-world for the example: Part of a UNenvironment.

Some mini-world entities:

STUDENTs

COURSEs

SECTIONs (of COURSEs)

(academic) DEPARTMENTs

INSTRUCTORs

Note: The above could be expressed in thRELATIONSHIP data model.



Example of a Database(with a Conceptual Data Mode

Some mini-world relationships:

SECTIONs are of specific COURSEs

STUDENTs take SECTIONs

COURSEs have prerequisite COURSEs

INSTRUCTORs teach SECTIONs

COURSEs are offered by DEPARTMENTs

STUDENTs major in DEPARTMENTs

Note: The above could be expressed in thRELATIONSHIP data model.



Characteristics Of Database

In file system each applications is free to namelement independently. Each user define andimplements the file needed for a specific softwapplication as a part of programming the ap

In database a single repository of data is maithat is defined once and than accessed by vusers.

In a database the name or labels of data are

once, and use reportedly by queries, transactapplication.



Typical DBMS Functionality

• Define a database : in terms of data types, sand constraints

• Construct or Load the Database on a seconstorage medium

• Manipulating the database : querying, genereports, insertions, deletions and modificatcontent

• Concurrent Processing and Sharing by a seand programs – yet, keeping all data valid aconsistent



Typical DBMS Functionality

Other features:

▫ Protection or Security measures to preventunauthorized access

▫ “Active” processing to take internal actions o

▫ Presentation and Visualization of data



Actor on the scene

A person typically defines, constructs, and mathe database.

In large organization, many people are responthe design, use and maintenance of a large dwith hundreds of user.

We call these users as the actors on the scene

Database Administrator.

Database Designer.

End Users.



Database Administrator

In any organization where many people use tresources, there is a need for a chief administoversee and manage these resources.

In a database environment, the primary resoudatabase itself, and the second resource is thand related software.

Administrating these resources is the responsibdatabase administrator (DBA).

The DBA is responsible for authorizing access tdatabase, co-ordinating and monitoring its usacquiring software and hardware resources a



Database DesignerDatabase designer are responsible for

identifying the data to be stored in thedata and for choosing appropriate

structures to represent and store thisdata.

These task should be done before thedatabase actually implemented andpopulated with data.

It is the responsibility of the databasedesigners to communicate with theend users to know their actualrequirement and to create adatabase that meet their requirement.



End Users

End users are the people whose job require acthe database for querying, updating and genreports;

There are two kinds of end users:

Casual User:

These kinds of user occasionally access the dabut they may need different information each

use database queries query language to specrequests.

Naive and Parametric Users:

These users are constantly querying and updadatabase, using standard type of query and u



End Users (cont.)

Example of Naive and Parametric users are

Bank tellers check account balances and post wit

and deposits.

Reservation clerks for airlines, hotels, and cars rent

companies check availability for a given request a

reservations.

Sophisticated End Users:

It include engineers, scientist, business analyst who

with the DBMS in order to implement their applica

Standalone Users:

Maintain personal database by using ready-made

packages that helps them through graphical repr



Workers Behind the Scene

DBMS system designers and implementers:

These people design and implement the DBMinterfaces as a software packages.

A DBMS consist of complex components or mimplementing the catalogue, processing quecontrolling concurrency and handling data resecurity.

Tool Designer:

These people design and implement tools. Thepackages that facilitate database modelling database system design and implement perfo



Workers behind the scene (cont

Operators and Maintenance Personal:

These person are responsible for the actual rumaintenance of the hardware and softwareenvironment for the database system.



Database Management System

Database Management System.

A database management system, or DBMS, is softwareassist in maintaining and utilizing large collections of daneed for such systems, as well as their use, is growing ra

Database Management system – Management of datManagement of Users

Software package for defining and managing a datab

Examples:

Proprietary: MS Access, MS SQL Server , DB2, Oracle,

Open source: MySql, PostgreSQL

http://office.microsoft.com/en-us/FX010857911033.aspx

http://www.microsoft.com/sql/default.mspx

http://www-306.ibm.com/software/data/db2/

http://www.oracle.com/index.html

http://www.mysql.com/

http://www.postgresql.org/

http://www.postgresql.org/

http://www.mysql.com/

http://www.oracle.com/index.html

http://www-306.ibm.com/software/data/db2/

http://www.microsoft.com/sql/default.mspx

http://office.microsoft.com/en-us/FX010857911033.aspx



Implication Of Using The Database Ap



Implication Of Using The Database Ap Potential for Enforcing Standards:

In large organization certain standards are made in order to communication and co-operation among various departmeand users within the organization.

Standards can be defined for names and formats of data eleformats, report structures, terminology and so on.

Reduced Application Development Time:

Designing a database from scratch takes more time than a f

however once the database is created, it is so easy to retrievdatabase.

Flexibility:

It may be necessary to change the structure of the databaseinclusion of new entities. Nowadays DBMS allow certain type

changes to the structure of the database.

I li ti f th D t b A h



Implication of the Database Approach

Availability Of Up-to-Date Information:

DBMS make the update database available to a

important at some industries to retrieve the updadatabase.

The availability is essential for many transaction-papplications, such as reservation systems or bank

Economies Of Scale:

The DBMS approach permits consolidation of datapplications.

This enables the whole organization to invest in mprocessors, storage devices, or communication ra

a weaker equipment's in each departments.



Advantages of Database

• Reduction of redundancy.

Avoid storing the data multiple times.

• Restricting Unauthorized Access.

• Avoidance of inconsistency.

• Provide Storage Structure for efficient Query Proce

•

Share ability. • Provide Backup and Recovery.

• Improved security.

• Provide Multiuser interface



• Provide Multiuser interface.

• Representing Complex Relationship among Data

• Enforcing Integrity Constraint.

Integrity constraint involves specifies a data typ

item.

Uniqueness in data- a course_name should havcourse name.

Disdvantages of Database

Higher cost

Conversion cost

Most difficult recovery



When Not To Use Database

In spite of advantages of using the database, theresituation in which a DBMS may involve unnecessarySome of them are listed below:

High initial investment in hardware, software and tra

The generality that a DBMS provides for defining anthe data.

Overheads for providing the security, concurrency

recovery, and integrity functions. Problem arise when the database are not properly

Simple file system are use for simple, well defined dapplication that are not expected to change.



Application Of DatabaseManagement System.

Hospital Management

System. Hotel Management

System.

Flight AviationManagement

UniversityManagement System.

IT Inventory etc.



Summary

Introduction

Basic definitions

Database

Data

Mini world

DBMS

Database systems

An example database

Applications of database

Advantages Of Database

Functionalities of database systems

Characteristics of database systems



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