11 COSC 2810 Systems Analysis and Design ●Instructor: Quinn Shao ●E-mail: [email protected]@webster.edu ●Online course info:

11

COSC 2810 Systems Analysis and Design

● Instructor: Quinn Shao● E-mail: [email protected]● Online course info:

http://ereserves.webster.edu (Electronic Reserves and Course

Materials)

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What is System Analysis and Design?

● Step by step process developing high- quality information system.

What is information system?● Combination of 1. IT 2. People 3. data

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Introduction

● Companies use information as a weapon in the battle to increase productivity, deliver quality products and services, maintain customer loyalty, and make sound decisions.

● Information technology can mean the difference between success and failure

Figure 1-1

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The Impact of Information Technology

● Information Technology – Combination of hardware and software

products and services that companies use to manage, access, communicate, and share information

– A vital asset that must be used effectively, updated constantly, and safeguarded carefully

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● The Future of IT– Responsible

for half of all productivity growth and a third of all economic growth between 1995-1999

Figure 1-3

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● The Role of Systems Analysis and Design– Systems Analysis and Design

• Step-by-step process for developing high-quality information systems

– Systems Analyst• Plan, develop, and maintain

information systems

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Information System Components

● A System is a set of related components that produces specific results

● Information systems have five key components: hardware, software, data, processes, and people

Figure 1-6

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Figure 1-9

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● Hardware – Everything in the physical layer of the

information system (server, workstation, network, computer, devices)

– Moore’s Law accurately predicted that computer processing power would double every 18 to 24 months


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● Software– System software (OS, security SW)– Network operating system (NOS)– Application software (Word, Access, Spreadsheets)

– Enterprise applications (order processing SW,

Payroll sys.)– Horizontal system (can be adapted for use in many

different companies, inventory sys. Payroll sys.)– Vertical system (special purpose sys.: web-based

retailer, medical sys.)– Legacy systems: a new sys. Must be able to

exchange data with older application)

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● Data – The raw

material that an information system transforms into useful information (database)

Print a paycheck by linking different database tables

Figure 1-11

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● Processes – Describe the tasks and business functions

that users, managers, and IT staff members perform to achieve specific results

● People– Users, or end users, are the people who

interact with an information system, both inside and outside the company

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The primary purpose of an information system is to provide valuable info to users.

Success or failure of a system depends on whether user are satisfied with the

sys’s output and operations.successful info. depends on the skilled professionals like, sys. analyst, programmers, DBAs.

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Understanding The Business

IT professionals must understand a company’s business operations in order to design successful systems. (a retail store or a hotel chain has unique info sys. requirements)

● Business Profile– Overview of a company ( products, service

through interview)● Business Models

– Graphical representation of one or more business processes

Figure 1-12

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Understanding The Business

● New Kinds of Companies● Companies are classified based

on their main activities:– Production-oriented (Intel, Motorola,

Cisco)– Service-oriented (Oracle, Amazon.com,

Office Depot)– Brick-and-mortar (traditional companies)– Dot-com (.com)

Figure 1-14

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Impact of the Internet

● E-Commerce (I-Commerce) - electronic commerce

– Internet-based commerce

● B2C (Business-to-Consumer)– Consumers can go online to purchase a

variety of products and services

● B2B (Business-to-Business)– Enables smaller suppliers to contact large

customers and allows purchasers to obtain instant information about market prices and availability

(Ford buy Firestone tires, builders buy lumber)

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Types of information system

● Today, Systems are identified by its functions, rather than by users – Enterprise computing systems– Transaction processing systems– Business support systems– Knowledge management systems– User productivity systems

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● Enterprise computing systems– Information systems that support

company-wide operations and data management

– To integrate a company’s primary functions (production, sales, services, inventory control, and accounting)

Figure 1-17

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● Transaction processing systems– Process data

generated by day-to-day business operations: customer order processing, accounts receivable, warranty, claim processing

Figure 1-18

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● Business support systems– Provide job-related information to users

at all levels of a company (travel pattern of rental car on holiday weekend)

– Use What-if analysis to increase profit. (add charge to bad weather delivery or

overload delivery)

Figure 1-19

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● Knowledge management systems– Simulate human reasoning (strict logic

and fuzzy logic)

Figure 1-20

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● User productivity systems– Technology that improves productivity: e-

mail, voice mail, fax, video conference, internet to

share data

● Information systems integration– Most large companies require systems that

combine transaction processing, business support, knowledge management, and user productivity features:

Combination of different types of info system.

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Information System Team

Organization model

Figure 1-21

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Systems Development Tools and Techniques

● Systems analysts must know how to use a variety of techniques such as modeling, prototyping, and computer-aided systems engineering (CASE )tools to plan, design, and implement information systems

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● Modeling– A system analyst can describe and simplify

an information system by using a set of business, data, object, and process models.

– A business model describes the info that a sys must provide.

– A data model describes data structure and design

– An object model describes objects (combine data and processes)

– A process model describes the logic a programmer uses to write modules.

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● Prototyping– Early working version of an information

system as an initial model to evaluate finished sys.

– Speeds up the development process significantly

– Can be an extremely valuable tool but can be made too early before IT issues are fully understood.

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● Computer-Aided Systems Engineering (CASE) Tools (Tool kit part 2)– CASE uses powerful software to help

systems analysts develop and maintain information systems

Microsoft Visio for drawing charts, diagrams.

Figure 1-22

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Systems Development Methods

● Structured Analysis– traditional systems development technique – Uses the Systems Development Life Cycle

(SDLC) to plan, analyze, design, implement, and support an information system. F1-25 shows a process that accepts

input data from 2 sources and transforms it into output data.

Figure 1-25

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● Object-oriented (O-O) analysis– combines data and the processes that act

on the data into things called objects– Systems analysts use O-O to model real-

world business processes and operations

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● Object-oriented (O-O) analysis

Figure 1-26

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● Joint Application Development and Rapid Application Development– JAD – Team based fact finding– RAD – compressed version of the entire

process(More details about JAD and RAD in Chapter

3)

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● Other development methodologies– In addition to structured analysis and O-O

methodologies, you might encounter other systems development techniques

– Microsoft Solutions Framework (MSF) documents the experience of its own IT teams

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The Systems Development Life Cycle

● SDLC used to plan and manage the systems development process.

● It includes the following steps:1. Systems planning2. Systems analysis3. Systems design4. Systems implementation5. Systems operation and support

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Figures 1-28 & 1-29

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● Systems planning– Purpose is to identify the nature and

scope of a problem. – Systems request – begins the process &

describes problems or desired changes.– Systems planning includes preliminary

investigation, which is a feasibility study that anticipates cost and benefit. Make recommendations on technical, economic, and time factors.

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● Systems Analysis– Purpose is to build a logical model of the

new system– First step is requirements modeling,

where you investigate business processes and document what the new system must do. (through interview)

– End product is the System requirements document.

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The Systems Development Life Cycle (SDLC)

● Systems Design– Purpose is to create a blueprint that will

satisfy all documented requirements– Identify all inputs, processes and outputs– Avoid misunderstanding through

manager and user involvement– End product (document) is system design

specification

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● Systems Implementation– New system is constructed– Implement, test, & install systems– File conversion occurs– Users, managers, IT staff trained to

operate and support the system– System evaluation performed (if sys

works properly)– Outcome of this phrase: system is ready

for use

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● Systems Operation and Support– IT staff maintains and enhances the

system– Enhancements provide new features and

benefits– Well-designed system will be reliable,

maintainable, and scalable

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● Systems Development Guidelines– Stick to a plan, complete phases in sequence– Involve users, fully understand user’s

requirements– Identify milestones for proceed or reject– Establish checkpoints to ensure project on

schedule– Be flexible, sys development is a dynamic

process– Provide accurate and reliable cost and

benefit information

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Information Technology Department

● The information technology (IT) department develops and maintains a company’s information systems. IT structure:

Figure 1-30

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● Application Development– Team may include users, managers and

IT Staff members

● Systems Support– Provides hardware and software support

● User Support– Provides users with technical information,

training, and productivity support

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● Database Administration– Database design, management, security,

backup, and user access

● Network Administration– Includes hardware and software

maintenance, support, and security

● Web Support– Design and construction of web pages

and presence. Important for e-commerce

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The Systems Analyst Position

● A systems analyst investigates, analyzes, designs, develops, installs, evaluates, and maintains a company’s information systems

● On large projects, the analyst works as a member of an IT department team.

● Smaller companies often use consultants to perform the work

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Chapter Summary

● IT is a combination of hardware, software, and telecommunications systems that support business

● The essential components of an information system are hardware, software, data, processes, and people

● Companies are production oriented, service oriented, or a combination of the two.

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Chapter Summary

● Based on their function and features, information systems are identified Organization structure usually includes levels

● Systems analyst use modeling, prototyping, and CASE tools

● Various development methodologies exist, including structured analysis and object-oriented analysis

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Chapter Summary

● The Systems Development Life Cycle1. Systems planning2. Systems analysis3. Systems design4. Systems implementation5. Systems operation and support

● An IT department develops, maintains and operates a company’s information systems

● Systems analysts need a combination of technical and business knowledge, analytical ability, and communication

Chapter 1 Complete

Documents

11 COSC 2810 Systems Analysis and Design ●Instructor: Quinn Shao ●E-mail: [email protected]@webster.edu ●Online course info: