Computers Are Your Future Tenth Edition Chapter 13: Systems Analysis & Design Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall1.

Computers Are Your FutureTenth Edition

Chapter 13: Systems Analysis & Design

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 1

2

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic,

mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Printed in the United States of America.

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall

What You Will Learn

Explain what systems analysts do. Understand the concept of a

system and its life cycle. Discuss why the systems

development life cycle (SDLC) is so widely used.

List the five phases of the SDLC.


What You Will Learn

Describe the classic mistakes of failed information systems development projects and how systems analysts can avoid them.

Discuss the activities in each of the five phases of the SDLC.

Name the deliverables of each of the five phases of the SDLC.


Systems Analysis & Design


System Analysts: Communication Counts

Systems analysis Involves information systems planning,

development, and maintenance Performed in an organized manner

System analysts determine the information system requirements of an organization based on input from users and management.


System Analysts: Communication Counts

Systems analysts must possess excellent communication and listening skills to help develop an effective information system.


The Systems Development Life Cycle

Development of information systems Used to be chaotic Often resulted in inadequate results

Systems development life cycle (SDLC) Means to organize development Consists of five phasesCopyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 8




Systems Made up of a grouping of parts that

work together to achieve an objective Have life cycles that start with their

creation, go through growth and changes, and end with obsolescence.

Artificial system: Developed by people rather than by nature



The system development life cycle’s philosophy: You cannot proceed to the

next phase before the previous one is completed.

Each phase must provide a deliverable that often serves as the input for the next phase.



Systems development wisdom: Involve users. Use a problem-solving methodology

to provide effective results. Use strong project management

skills.



Systems development wisdom (continued): Document all important facts about a

project. Use checkpoints to keep work on

target. Anticipate future growth and change

while designing the system.


The Systems Development Life Cycle An accepted

concept in the systems development life cycle is the waterfall model, which enables analysts to revisit a prior phase through corrective pathways when problems arise.


Phase 1: Planning the System

Phase 1 includes the following tasks: Recognizing the needs of the system Defining the problem Examining alternative solutions Developing a plan Determining feasibility Preparing the project proposal



Recognition of the need for a new or modified system may come from acknowledging deficiencies.



Defining the problem cannot occur until it is understood Problem: the underlying cause of a

symptom Symptom: the unacceptable result of

a problem Once the problem is defined:

Use requirements analysis to identify the system requirements based on user needsCopyright © 2009 Pearson Education, Inc. Publishing as Prentice

Hall 17


After system requirements are defined: Evaluate potential solutions Create a project plan

Cites the goals of the system Lists the steps or activities to successful

completion of the project Specifies order of completion Estimates time frames



Gantt chart Type of bar chart Used to provide a graphical summary

of the milestone tasks and their due dates.



Feasibility studies Technical feasibility: Can be

completed with existing technology Operational feasibility: Can be

accomplished with the available resources

Economic feasibility: Can be done with the available fiscal

resources Often involves a cost-benefit analysis Seeks a return on investment (ROI)



Project proposal Phase 1 deliverable A written report

Documents details of the system problem and its resolution

Concludes with a recommendation. End of Phase 1 Basis for management decision to

proceed Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 21

Phase 2: Analyzing & Documenting the Existing System

Determine what the new system will do

Two parts: Analyzing the current system Determining the requirements of the

new system Deliverable: List of requirements

for the new systemCopyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 22

Phase 3: Designing the System

Determine how the new system information will work List and document specifications

using Graphic tools Project dictionaries Data dictionaries



Design tools used during this phase: Entity-relationship diagram (ERD) Data flow diagram (DFD) Rapid application development (RAD) Computer-aided software engineering

(CASE)




Entity relationship diagram


Rapid Application Development (RAD) Also known as prototyping Create small mock-up of system early in

the process Provide enough functionality to get

feedback from users Advantage: Users have something

concrete to reviewCopyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 26


Computer-Aided Software Engineering (CASE) For complex systems Automates documenting entity

relationships and data flow CASE tools include project management

features, data dictionaries, documentation support, and graphical output support, and some generate prototype code Copyright © 2009 Pearson Education, Inc. Publishing as Prentice

Hall 27


Teams create support material: Project dictionary: defines

terminology Data dictionary: identifies the data

that will be entered into the system



Phase 3 deliverable: A logical diagram or design that shows how the new system will operate


Phase 4: Implementing the System

Decide whether to create system or outsource development

Additional tasks: Developing the software Application and acceptance testing User training System conversion



Application testing involves assessing the programs separately and as a group.

Acceptance testing is performed by the users and ensures that the system works properly.



System conversion methods: Parallel conversion Pilot conversion Phased conversion Direct conversion (crash conversion)

The deliverable in Phase 4 is the completed, tested system.


Phase 5: Maintaining the System

Review and maintain new system Must meet the needs of the users Must function properly

Perform postimplementation system review Evaluates whether the goals of the

system are met Serves as Phase 5 deliverable


Computers Are Your FutureTenth Edition

Chapter 12: Databases & Information Systems


Databases & Information Systems


The Levels of Data in a Database

A database is a group of data that can be entered, selected, sorted, grouped, reviewed, and produced as output.



Database units Bit

The smallest unit of data stored by a computer

Contains either a 1 or a 0 Character

A letter, number, or symbol Made of bytes, which are groups of 8 bits



Database terms Field

Composed of one or more characters Identified by its field name

Record Group of related fields Is contained in tables or data files

Primary key or key field Unique identifier for each record




Types of Database Programs

Two types of database programs, software used to create databases and use their data File management programs

Manage only one table or file Known as a flat file

Database management systems (DBMS)

Manage multiple tables or filesCopyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 40


File management systems are: Useful for personal or small business

needs Used to develop an uncomplicated

computerized system for information storage and retrieval

Inexpensive and easy to use Unable to link to data stored in other

filesCopyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 41


Database management systems (DBMS) are: Able to access, store, and edit data Available in a variety of forms Not usually tied to one particular platform Able to present information in various

formats



Database management systems (DBMS)



Database management system classifications Based on how information is organized and

retrieved Four main DBMS classifications

Flat Hierarchical Network Relational database management system (RDBMS)



Relational database management systems (RDBMS) Most widely used class of DBMS Link data found in several tables or

files Compared with file management

programs: More expensive Harder to learn Better in controlling data redundancy Better in preventing potential data errorsCopyright © 2009 Pearson Education, Inc. Publishing as Prentice

Hall 45


Data warehouses Combine all the data of an

organization into one large database Help executives make decisions

Examine data through the drill-down method

View performance data for whole company

Search through individual department data

Data marts are similar but support a department or division



Data mining Method used for

data review and investigation

Can be used to determine unknown data patterns



Client/server database systems Use database server software that

reacts to the information requests of remote users

Also use database client software to provide an interface with the user

Use queries to request information from the database server

Examples: ATMs and online bankingCopyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 48


Web-database integration involves taking database information and making it accessible over the Internet.


Advantages of Database Management Systems

Characteristics of a good database: Data integrity Data independence Avoiding data redundancy Data security Data maintenance



Data within a database is considered to have data integrity if that data is considered valid.

Data validation techniques are used as an attempt to prevent data integrity errors.



Data independence Data that controls applications and

data stored in the database are kept separate.

Avoiding data redundancy Enter data only once. Multiple entry of the same data is a

sign of an inadequately developed system.



Data security: Prevents a database’s contents from being accessed by unauthorized users.

Data maintenance: Required to permit the proper care and protection of data.


Information Systems: Tools for Global Competitiveness

A skillfully created information system: Integrates data, computer hardware,

software, procedures, and users Main functions include:

Accepting data Converting data into information Storing data Distributing the information



Methods for controlling information include: Only routing information

to appropriate users Summarizing information Ensuring information

selectivity Getting rid of needless

information that wastes time and resources



Each of the core functions of an organization is managed by the appropriate functional division (functional unit, functional area).




Functional divisions of an organization: Accounting and finance Marketing and sales Human resources Management Manufacturing Information systems

Information Systems in Organizations: A Survey

For retailers, computers and databases are no longer used solely for traditional applications.

Point of sales (POS) cash registers are computers that integrate credit card authorization and inventory systems and are used as marketing devices.


Information Systems in Organizations: A Survey

Other systems that retailers use include: Check-screening systems, which

determine if a check is written on a delinquent account

Signature capture systems, which obtain digital customer signatures

Photo checkout systems, which show the photo of a customer at the time a credit card is used


Computers Are Your Future Tenth Edition Chapter 13: Systems Analysis & Design Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall1.

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