slides of data base

7/29/2019 slides of data base

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Database


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Industrial Scope

Dataware housing

Ebanking

Police Criminal record NADRA

Datamining

FIA database Macodonalds


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What is Data ?


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Definition of Data

Data consists of Facts, text, graphics,

images, sound and video segments that

have meaning to users environment.Data can exist in a variety of forms:

- As numbers or text on pieces of paper

- As bits and bytes stored in electronicmemory

- As facts stored in a person's mind.


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Data Type

Data is what we measure

Data type refers to the classification of a

particular type of information

integer floating point

character, string

date student record

blob (binary large object)


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Data in Context

Large volume of facts, difficultto interpret or make decisions

based on


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INFORMATION

Data that has been processed

in such a way that it canincrease the knowledge of

person who uses it


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Useful information that managers can use fordecision making and interpretation


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Data vs Information

Data into information

Summarise data

Data In context (table)Decision support

We use Database term withoutdistinguish data or information


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ACTIVITY

Please write down the data for cricket match

bowling

Do you get any information??


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Definition of Database

Database is a shared collection of logicallyrelated data, designed to meet the information

needs of multiple users in an organization

Database is designed, built, and populatedwith data for a specific purpose. It has an

intended group of users and preconceived

applications in which these users are

interested.


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Alternative Terminology

D a ta P ro ce ssin g T e rm s

F o r m a l T e r m s A l te r n a ti v e 1 A l te r n a ti v e 2

R e la tio n T a b le F i le

T u p le R o w R e c o rd

A ttr ib u te C o lu m n F ie ld

Formal terms are mostly used for technical users.

Data processing terms are more natural for non

technical users.


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Computerized FileBased Processing

System


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File-based Systems

A collection of application programs that

perform services for the end users (e.g.

reports). Each program defines and manages its

own data.


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Computerized File-basedProcessing

File handling routines &

File definition

SalesSales files

File handling routines &File definition

ContractsContracts files


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Three file processing systems

Duplicate

Data

Li it ti f C t i d Fil b d


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Limitation of Computerized File-basedApproach

Separation and Isolation of data Each application maintains its own set of data.

Users of one application may be unaware of potentially

useful data held by other applications.

Duplication of data (data redundancy) Same data is held by different files.

Limited Data SharingNo centralized control of data

Lengthy Development TimesProgrammers must design their own file formatsExcessive Program Maintenance

80% of information systems budget

Li it ti f Fil b d


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Limitation of File-basedApproach

Accessibility Data is stored using programs that are written indifferent languages and format

Cannot easily access other files due to incompatible file

format.

No control over access and manipulation of data beyond

that imposed by application programs.

Hard Coded Queries (Data dependence) File structure and all definition of data are defined in the

application program code.

Programs are written to satisfy particular functions /

requirements.

Any new requirement needs a new program.


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Problems with Data Dependency

Each application programmer must maintain theirown data

Each application program needs to include codefor the metadata of each file

Each application program must have its ownprocessing routines for reading, inserting,updating and deleting data

Lack of coordination and central control

Non-standard file formats


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Problems with Data Redundancy

Waste of space to have duplicate data

Causes more maintenance headaches The biggest Problem:

When data changes in one file, could cause

inconsistencies Compromisesdata integrity


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Database Processing

System

SOLUTION:


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Database Processing

Sales

ContractsApplication

Contracts

Database

SalesApplication

DBMS


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The DATABASE Approach

Central repository of shared data

Data is managed by a controlling agent

Stored in a standardized, convenient

form

Requires a Database Management System (DBMS)

D b M S


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Database Management System

DBMS manages dataresources like an operating

system manages hardware

resources

DBMS Databasecontainingcentralizedshared data

Application#1

Application

#2

Application

#3


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Database Management System (DBMS)

A collectionofprograms that enables users to

define,create and maintain and control access to the

database.

General-purpose software system that facilitates the

processes ofdefining, constructing and

manipulating databases for various applications.

Defining - specifying data types, structures, constraints.

Constructing - storing of data

Manipulation - querying, updating and reporting.


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Popular DBMS In The Market

Sybase SQL Anywhere

Informix Dynamic Server

Borland Interbase


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Database Management System

A DBMS is a data storage and retrievalsystem which permits data to be stored

non-redundantly while making it appear to

the user as if the data is well-integrated.


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Advantages of Database Approach

Program-Data Independence Metadata stored in DBMS, so applications dont need to worry

about data formats

Data queries/updates managed by DBMS so programs dont

need to process data access routines Results in: increased application development and maintenance

productivity

Minimal Data Redundancy

Leads to increased data integrity/consistency


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Advantages of Database Approach

Improved Data Sharing

Different users get different views of the data

Enforcement of Standards All data access is done in the same way

Improved Data Quality Constraints, data validation rules

Better Data Accessibility/ Responsiveness

Use of standard data query language (SQL)

Security, Backup/Recovery, Concurrency

Disaster recovery is easier

C t d Ri k f th


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Costs and Risks of the

Database Approach

Up-front costs: Installation Management Cost and Complexity Conversion Costs

Cost of DBMS

Additional hardware costs.

Ongoing Costs:

Requires New, Specialized Personnel

Need for Explicit Backup and Recovery Higher impact of a failure

Organizational Conflict:

Old habits die hard


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The Range of

Database Applications

Personal Database standalone desktopdatabase

Workgroup Database local area network(


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PersonalComputer

Database


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Workgroup database with local area network


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Anenterprise

datawarehouse

Components of


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Components ofDBMS Environment

1. HardwareCan range from a PC to a network of computers.

2. Software

DBMS itself and operating system, including anynetwork software if network is being used.

3. DataIncludes actual data used by the organization, anddescription of data (schema). Also a systemcatalog contains data such as the names ofauthorized users.

C f


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Components ofDBMS Environment

4. ProceduresInstructions and rules that should be applied to thedesign and use of the database, and the use ofthe DBMS.

5. PeopleData & Database AdministratorDatabase Designer :- Logical & Physical

Application ProgrammersEnd Users


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DBMS Environment

Software

Hardware

Procedures

People

Machine Human

Data

Bridge


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Database SystemEnvironment

Users/Programs

Application Programs/Queries

Software to ProcessQueries/Programs

Software to Access Stored Data

Stored DatabaseDefinition

StoredDatabase


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Evolution of DB Systems

Flat files - 1960s - 1980s

Hierarchical 1970s - 1990s

Network 1970s - 1990s Relational 1980s - present

Object-oriented 1990s - present

Object-relational 1990s - present Data warehousing 1980s - present

Web-enabled 1990s - present


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Summary

Course Contents Data

Information

Data Vs Information

Database Terms DBMS

Advantages

Disadvantages of DBMS

Database Terms

Comparison of Computerized File Based Processing System &Database System

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