FIT328 01 Introduction Database Environment

7/30/2019 FIT328 01 Introduction Database Environment

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LECTURE 1

PART I - INTRODUCTION

[DBS328] Database Systems

DBS328 Course Contents

Design of databasesE-R model, relational model

Database programmingSQL, Relational algebra

Database server environmentmySQL, PHP


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DBS328 Course Requirements

Project : a simple website using mySQL databaseTeam work / individual work Presentation + Q&A

Weekly quiz & AssignmentsMidterm

Paper-basedClosed book

Final ExamPaper-basedClosed book Project weights 50% of Final Exam.

DBS328 Course Assessment

5% Attendance Attend at least 80% of classes

10% Assignments No late submission is allowed

10% Weekly Quiz 15% Midterm60% Final Examination

Requirement: score at least 20% (of 40%) before FE. 30% Final Project 30% Paper-based Exam


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Textbook

Modern DatabaseManagement8 th Edition

Jeffrey A. Hoffer

Mary B. Prescott Fred R. McFadden

[DBS328] Database Systems

LECTURE 1

PART IITHE DATABASE ENVIRONMENT


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Credits

Modern Database Management, 8 th editionby: Jeffrey A. Hoffer, Mary B. Prescott,

Fred R. McFadden 2007 by Prentice Hall

Objectives

Definition of termsExplain growth and importance of databasesName limitations of conventional file processingIdentify five categories of databasesExplain advantages of databasesIdentify costs and risks of databasesList components of database environmentDescribe evolution of database systems


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Definitions

Database : organized collection of logically related dataData : stored representations of meaningfulobjects and events

Structured: numbers, text, datesUnstructured: images, video, documents

Information : data processed to increaseknowledge in the person using the dataMetadata : data that describes the propertiesand context of user data

Figure 1-1a Data in context

Context helps users understand data


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Figure 1-1b Summarized data

Graphical displays turn data into useful information thatmanagers can use for decision making and interpretation

Disadvantages of File Processing

Program-Data Dependence All programs maintain metadata for each file they use

Duplication of DataDifferent systems/programs have separate copies of the same dataLimited Data Sharing

No centralized control of data

Lengthy Development TimesProgrammers must design their own file formats

Excessive Program Maintenance80% of information systems budget


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Problems with Data Dependency

Each application programmer must maintainhis/her own dataEach application program needs to includecode for the metadata of each fileEach application program must have its ownprocessing routines for reading, inserting,updating, and deleting dataLack of coordination and central controlNon-standard file formats

Figure 1-3 Old file processing systems atPine Valley Furniture Company


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Problems with Data Redundancy

Waste of space to have duplicate dataCauses more maintenance headachesThe biggest problem:

Data changes in one file could causeinconsistenciesCompromises in data integrity

SOLUTION: The DATABASE Approach

Central repository of shared dataData is managed by a controlling agentStored in a standardized, convenient form

Requires a Database Management System (DBMS)


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Database Management System

A software system that is used to create, maintain,and provide controlled access to user databases

Order FilingSystem

InvoicingSystem

PayrollSystem

DBMSCentral database

Contains employee,order, inventory,

pricing, andcustomer data

DBMS manages data resources like an operating system manages hardware resources

Advantages of the Database Approach

Program-data independencePlanned data redundancy

Improved data consistency Improved data sharingIncreased application development productivity Enforcement of standardsImproved data quality Improved data accessibility and responsivenessReduced program maintenanceImproved decision support


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Costs and Risks of the Database Approach

New, specialized personnelInstallation and management cost and complexity Conversion costsNeed for explicit backup and recovery Organizational conflict

Elements of the Database Approach

Data modelsGraphical system capturing nature and relationship of dataEnterprise Data Model high-level entities and relationships forthe organizationProject Data Model more detailed view, matching data structurein database or data warehouse

Relational DatabasesDatabase technology involving tables (relations) representingentities and primary/foreign keys representing relationships

Use of Internet Technology Networks and telecommunications, distributed databases, client-server, and 3-tier architectures

Database Applications Application programs used to perform database activities (create,read, update, and delete) for database users


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Segment of an Enterprise Data Model

Segment of a Project-Level Data Model

One customer may place manyorders, but eachorder is placed by

a single customer One-to-many

relationship


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One order hasmany order lines;each order line isassociated with asingle order

One-to-manyrelationship

One product can be in manyorder lines, eachorder line refersto a single

product

One-to-manyrelationship


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Therefore, oneorder involvesmany productsand one product isinvolved in manyorders

Many-to-manyrelationship

Figure 1-4 Enterprise data model for Figure 1-3 segments


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Figure 1-5 Components of the Database Environment

Components of the Database Environment

CASE Tools computer-aided software engineeringRepository centralized storehouse of metadataDatabase Management System (DBMS) softwarefor managing the databaseDatabase storehouse of the data

Application Programs software using the dataUser Interface text and graphical displays to usersData/Database Administrators personnelresponsible for maintaining the databaseSystem Developers personnel responsible fordesigning databases and softwareEnd Users people who use the applications anddatabases


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The Range of Database Applications

Personal databases Workgroup databasesDepartmental/divisional databasesEnterprise database


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Figure 1-6Typical datafrom apersonaldatabase

Figure 1-7 Workgroup database withwireless local area network


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Enterprise Database Applications

Enterprise Resource Planning (ERP)Integrate all enterprise functions (manufacturing, finance,sales, marketing, inventory, accounting, human resources)

Data WarehouseIntegrated decision support system derived from variousoperational databases

Figure 1-8 An enterprise data warehouse


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Evolution of DB Systems

Documents

FIT328 01 Introduction Database Environment