Bài Giảng Phân Tích Và Thiết Kế Hệ Thống - Modern Systems Analysis And Design

Modern Systems Analysis and Design Ch1 Chapter 1 The Systems Development Environment Modern Systems Analysis and Design Seventh Edition Copyright © 2014 Pearson Education, Inc Publishing as Prentice H[.]

Chapter 1 The Systems Development

Environment

Modern Systems Analysis

and Design

Seventh Edition

Learning Objectives

 Define information systems analysis and design.

 Describe the information systems development life cycle (SDLC).

 Explain Rapid Application Development (RAD) and

computer-aided software engineering (CASE) tools.

 Describe Agile Methodologies and eXtreme

Programming.

 Explain object-oriented analysis and design and the

Rational Unified Process (RUP).

 Information Systems Analysis and Design

 Complex organizational process

 Used to develop and maintain

computer-based information systems

 Used by a team of business and systems

professionals

Introduction (Cont.)

Introduction (Cont.)

 Application Software

 Computer software designed to support

organizational functions or processes

 Systems Analyst

 Organizational role most responsible for

analysis and design of information systems

A Modern Approach to Systems

Analysis and Design

 1950s: focus on efficient automation of

existing processes

 1960s: advent of procedural third

generation languages (3GL) faster and

more reliable computers

 1970s: system development becomes

more like an engineering discipline

A Modern Approach to Systems

Analysis and Design (Cont.)

 1980s: major breakthrough with 4GL,

CASE tools, object-oriented methods

 1990s: focus on system integration, GUI applications, client/server platforms,

Internet

 The new century: Web application

development, wireless PDAs and smart

phones, component-based applications, application service providers (ASP)

Developing Information Systems

standard process followed in an

organization to conduct all the steps

necessary to analyze, design, implement, and maintain information systems.

Systems Development Life

Cycle (SDLC)

 Traditional methodology used to develop,

maintain, and replace information systems

Standard and Evolutionary Views of SDLC

Systems Development Life Cycle

(SDLC) (Cont.)

 Planning – an organization’s total

information system needs are identified, analyzed, prioritized, and arranged

studied and structured

 Design – a description of the

recommended solution is converted into logical and then physical system

Systems Development Life Cycle

(SDLC) (Cont.)

 Logical design – all functional features of

the system chosen for development in

analysis are described independently of

any computer platform

 Physical design – the logical

specifications of the system from logical

design are transformed into the

technology-specific details from which all

Systems Development Life Cycle

(SDLC) (Cont.)

is coded, tested, installed and supported in the organization

systematically repaired and improved

FIGURE 1-9

The heart of systems development

The Heart of the Systems Development Process

Current practice combines analysis, design, and implementation

FIGURE 1-8

Analysis–design–code–test loop

Traditional Waterfall SDLC

One phase begins when another

completes, with little backtracking and looping.

FIGURE 1-10

Problems with Waterfall Approach

 Feedback ignored, milestones lock in

design specs even when conditions

Different Approaches to Improving Development

Computer-Aided Software

Engineering (CASE) Tools

 Diagramming tools enable graphical

representation.

 Computer displays and report generators help prototype how systems “look and

feel”.

 IBM’s Rational products are the best

known CASE tools.

Computer-Aided Software

Engineering (CASE) Tools (Cont.)

 Analysis tools automatically check for

consistency in diagrams, forms, and

reports.

 A central repository provides integrated

storage of diagrams, reports, and project management specifications.

Computer-Aided Software

Engineering (CASE) Tools (Cont.)

 Documentation generators standardize

technical and user documentation.

 Code generators enable automatic

generation of programs and database

code directly from design documents,

diagrams, forms, and reports.

CASE Tools (Cont.)

FIGURE 1-11

Screen shot of ArgoUML, an open source CASE tool

(Source:

http://argouml.tigris.org/)

CASE Tools (Cont.)

Rapid Application Development

(RAD)

 Decreases design and implementation

time

 Involves: extensive user involvement,

prototyping, integrated CASE tools, code generators

 More focus on user interface and system function, less on detailed business

Rapid Application Development

(RAD) (Cont.)

FIGURE 1-12

RAD life cycle

Agile Methodologies

 Motivated by recognition of software

development as fluid, unpredictable, and dynamic

 Three key principles

 Adaptive rather than predictive

 Emphasize people rather than roles

Self-adaptive processes

When to use Agile Methodologies

 If your project involves:

 Unpredictable or dynamic requirements

 Responsible and motivated developers

 Customers who understand the process and will get involved

eXtreme Programming

 Short, incremental development cycles

 Automated tests

 Two-person programming teams

 Coding, testing, listening, designing

eXtreme Programming (Cont.)

 Coding and testing operate together

 Advantages:

 Communication between developers

 High level of productivity

 High-quality code

Object-Oriented Analysis and

Design (OOAD)

 Based on objects rather than data or processes

attributes and behaviors of a

real-world entity

Object-Oriented Analysis and

Design (OOAD) (Cont.)

objects sharing the same attributes

and behaviors

arrangement of classes enable

subclasses to inherit properties of

superclasses

Rational Unified Process (RUP)

 An object-oriented systems development methodology

 Establishes four phase of development:

inception, elaboration, construction, and transition

 Each phase is organized into a number of

separate iterations.

FIGURE 1-13

Phases of OOSAD-based development

Our Approach to Systems

Development

 The SDLC is an organizing and guiding

principle in this book.

 We may construct artificial boundaries or artificially separate activities and

processes for learning purposes.

 Our intent is to help you understand all the pieces and how to assemble them.

 In this chapter you learned how to:

 Define information systems analysis and design.

 Describe the information Systems Development Life

Cycle (SDLC).

 Explain Rapid Application Development (RAD),

prototyping, Computer Aided Software Engineering

(CASE), and Service-Oriented Architecture (SOA).

 Describe agile methodologies and eXtreme

programming.

 Explain Object-Oriented Analysis and Design

(OOAD) and the Rational Unified Process (RUP).

Copyright © 2014 Pearson Education, Inc

Chapter 2 The Origins of Software

Modern Systems Analysis

and Design

Seventh Edition

Jeffrey A Hoffer Joey F George Joseph S Valacich

 There are various sources of software for organizations.

 Most of a corporation’s application

software is created by external sources.

 Much in-house coding involves making

components work together.

 There are criteria to evaluate software

from different sources.

Systems Acquisition: Outsourcing

responsibility of some or all of an

organization’s information systems

applications and operations to an

outside firm

Systems Acquisition: Outsourcing (Cont.)

 Outsourcing Example

 Shell Oil outsource spending: $3.2

billion (2008)

 Shell’s outsourcing vendors

(2008-2011): EDS, T-Systems, AT&T, IBM,

Logica, Wipro, Accenture

Outsourcing (Cont.)

 Cost-effectiveness

 Take advantage of economies of scale

 Make up for lack of in-house knowledge

 Free up internal resources

 Reduce time to market

 Increase process efficiencies

Sources of Software

 Information technology services firm

 Packaged software producers

Sources of Software (Cont.)

Sources of Software (Cont.)

Information Technology (IT)

Services Firms

 Help companies develop custom

information systems for internal use

 Develop, host, and run applications for

customers

 Provide other services

Packaged Software Producers

 Serve many market segments

 Provide software ranging from based packages (i.e general ledger)

broad-to niche packages (i.e day care

management)

 Pre-packaged, off-the-shelf software

Packaged Software Producers

(Cont.)

 Software runs on all size computers, from

microcomputers to large mainframes.

 Prepackaged software is off-the-shelf,

turnkey software (i.e not customizable).

 Off-the-shelf software, at best, meets 70% of organizations’ needs.

Prepackaged Software

Figure 2-2 Microsoft Project (Source: Microsoft Corporation.)

Enterprise Solutions Software

integrate individual traditional business functions into modules enabling a single seamless

transaction to cut across functional boundaries.

 SAP AG is the leading vendor of ERP systems.

Enterprise Solutions Software (Cont.)

Figure 2-3 SAP’s Business ByDesign, a product designed for medium sized companies.

(Source: www.sap.com/usa/solutions/Sme/ Businessbydesign/Flash/bsm/A1S.html.

Cloud Computing

 The provision of computing

resources, including applications,

over the Internet, so customers do not have to invest in the computing

infrastructure needed to run and

maintain the resources

Cloud Computing (Cont.)

 Microsoft Azure platform

 Amazon.com cloud infrastructure and

services

Cloud Computing (Cont.)

 Heavy growth predicted

 Benefits:

 Free internal IT staff

 Faster access to application than via internal development

 Lower cost than internal development

 Concerns

 Security

Open Source Software

 Freely available including source code

 Developed by a community of interested

people

 Performs the same functions as commercial software

 Examples: Linux, mySQL, Firefox

 How to make money?

 Provide maintenance/services

 Sell a more featured version of the free software

In-House Development

 If sufficient system development expertise with the chosen platform exists in-house, then some

or all of the system can be developed by the

organization’s own staff.

 Hybrid solutions involving some purchased and some in-house components are common.

Sources of Software Components

Selecting Off-the-Shelf Software

developing the same system in-house with the cost of purchasing or

licensing the software package

 Functionality: the tasks that the

software can perform and the

mandatory, essential, and desired

system features

Selecting Off-the-Shelf Software (Cont.)

Selecting Off-the-Shelf Software (Cont.)

 Vendor support: whether and

how much support the vendor can provide and at what cost

 Viability of vendor: can vendor

continue to adapt/update software

to changes in systems software

and hardware

Selecting Off-the-Shelf Software (Cont.)

Selecting Off-the-Shelf Software (Cont.)

software is customized

up-to-date user’s manual and

technical documentation

Selecting Off-the-Shelf Software (Cont.)

software package to respond to the

user’s requests in an interactive

session

the difficulty of loading the software

and making it operational

Validating Purchased Software

Information

 Use a variety of information sources:

 Collect information from vendor

 Software documentation

 Technical marketing literature

Request For Proposal (RFP)

 A request for proposal (RFP) is a

document provided to vendors to ask them to propose hardware and

system software that will meet the

requirements of a new system.

Request For Proposal (RFP)

Information Sources For RFP

 Vendor’s proposal

 Running software through a series of tests

 Feedback from other users of the vendor’s product

 Independent software testing services

 Articles in trade publications

 The use of previously written software

resources, especially objects and

components, in new applications

 Commonly applied to two different

development technologies:

 Object-oriented development

Component-based development

Reuse (Cont.)

 Object class encapsulates data and behavior

of common organizational entities (e.g

employees)

 Components can be as small as objects or as large as pieces of software that handle single business functions

Reuse (Cont.)

reuse is the use of object classes

in more than one application (e.g Employee).

Reuse (Cont.)

reuse is the assembly of an

application from many different

components at many different

levels of complexity and size (e.g Currency conversion).

Costs and Benefits of Reuse

FIGURE 2-5

Approaches to Reuse

 Ad-hoc: individuals are free to find or

develop reusable assets on their own

practice reuse

Approaches to Reuse (Cont.)

adoption of reusable assets is mandated

they are being designed for specific

applications

Approaches to Reuse (Cont.)

 In this chapter you learned how to:

 Explain outsourcing.

 Describe six different sources of software.

 Discuss how to evaluate off-the-shelf

software.

 Explain reuse and its role in software

development.

Copyright © 2014 Pearson Education, Inc

Publishing as Prentice Hall

 List and describe the skills and activities of a project

manager during project initiation, project planning,

project execution, and project closedown.

 Explain what is meant by critical path scheduling and

describe the process of creating Gantt charts and

network diagrams.

 Explain how commercial project management software packages can be used to assist in representing and

 Project management (PM) may be the most important aspect of systems development.

 Effective PM helps to ensure

 The meeting of customer expectations.

 The satisfying of budget and time constraints.

 The nature of projects has changed from custom

development to implementing packaged software and data warehousing.

Pine Valley Application Project

FIGURE 3-1

Three computer applications at Pine Valley Furniture: order filling, invoicing, and payroll

Managing the Information Systems Project

 A controlled process of initiating, planning,

executing, and closing down a project

Managing the Information Systems Project (cont.)

 Project manager

 A systems analyst with a diverse set of skills— management, leadership, technical, conflict

management, and customer relationship—who

is responsible for initiating, planning,

executing, and closing down a project

 Deliverable

 The end product of an SDLC phase

Deciding on Systems Projects

 System Service Request (SSR)

 A standard form for requesting or proposing systems development work within an

organization

 Feasibility study

 A study that determines whether a requested system makes economic and operational

FIGURE 3-2

System Service Request for Purchasing Fulfillment System with name and contact information of the person requesting the system,

a statement of the problem, and the name and contact information

of the liaison and sponsor

Project Management Activities

FIGURE 3-4

A project manager

Phases of Project Management

PM Phase 1: Project Initiation

 Assess size, scope and complexity, and

establish procedures.

 Establish:

 Initiation team

 Relationship with customer

 Project initiation plan

 Management procedures

 Project management environment and workbook

FIGURE 3-6

The project workbook for the Purchase Fulfillment System project contains nine key documents in both hard-copy and electronic form.