Computers Are Your FutureEleventh Edition
Chapter 13: Systems Analysis & Design
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Systems Analysis & Design
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Objectives
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.
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Objectives
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.
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System Analysts: Communication Counts
Systems analysis Involves information systems planning,
development, and implementation Is performed in an organized manner
Systems analysts Have good listening and communication
skills Work with users and management Determine information system
requirementsCopyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 5
System Analysts: Communication Counts
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The Systems Development Life Cycle
Systems development life cycle (SDLC) Provides a systematic approach to
development Seeks to improve system quality Consists of five phases
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The Systems Development Life Cycle
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The Systems Development Life Cycle
System Is a collection of components working
together to achieve a goal Has a life cycle that starts with
creation, goes through growth and changes, and ends with obsolescence
Artificial system Developed by people rather than by
nature Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 9
The Systems Development Life Cycle
System development life cycle philosophy Don’t proceed to the next
phase before the current one works properly.
Each phase must provide a deliverable that often serves as the input for the next phase.
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The Systems Development Life Cycle
Avoid mistakes Involve users to ensure that the
system meets their needs. Use a problem-solving methodology
to provide effective results. Use strong project management
skills.
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The Systems Development Life Cycle
Avoid mistakes Document all important facts about a
project. Use checkpoints to keep work on
target. Anticipate future growth and change
while designing the system.
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The Systems Development Life Cycle
Waterfall model Builds correction
pathways into the process
Allows the team to return to a previous phase if problems develop in later phases
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The Systems Development Life Cycle
Modern approaches Prototyping is a small-scale mock-
up of a system but has some problems:
Incomplete analysis User confusion Time consuming
Joint application development Conducts SDLC phases 1–4 at the same
time Involves intense team member
interaction
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Phase 1: Planning the System
Recognizing the need for a system may come from acknowledging deficiencies.
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Phase 1: Planning the System
Defining the problem Know the difference between a
symptom and a problem: Symptom—An acceptable result of a
problem Problem—The underlying cause of a
symptom
Examining alternative solutions Complete a requirements analysis
to identify the requirements based on needs.
Consider possible solutions.
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Phase 1: Planning the System
Developing a plan Identify the appropriate solution. Create a project plan:
Cite the goals of the system. List activities for successful project
completion: Specify order of completion. Estimate time frames.
Create specifications.
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Phase 1: Planning the System
A Gantt chart summarizes plans
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Phase 1: Planning the System
Determining feasibility Technical feasibility: Can be completed
with existing technology Operational feasibility: Can be
accomplished with available resources Economic feasibility:
Can be done with available fiscal resources Often involves a cost-benefit analysis Seeks a return on investment (ROI)
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Phase 1: Planning the System
Preparing the project proposal Project leader writes a report:
Identifies the problem. Explains the proposed solution and
benefits. Gives details of the plan. Concludes with a recommendation.
The project proposal is the deliverable for phase 1.
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Phase 2: Analyzing & Documenting the Existing System
Analyzing the existing system Identify activities that need to be
retained. Uncover problems not evident in phase
1. Determining the new system
requirements State the requirements precisely. Provide a list as the deliverable from
phase 2.Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 21
Phase 3: Designing the System
Explains how the new system will work Shows data path and procedures in
graphical tools Entity-relationship diagrams (ERDs) Data flow diagrams Project dictionaries
The phase 3 deliverable is a logical diagram or design.
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Design tools Deliverable: Entity-relationship
diagram
Phase 3: Designing the System
Design tools Data flow diagram uses symbols for
data movement
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Phase 3: Designing the System
Design tools Team members develop:
Project dictionary: defines terminology Data dictionary: identifies data types
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Phase 3: Designing the System
Other design approaches Rapid application development
(RAD) Also known as prototyping. Create a small mock-up of system early in
the process. Provide enough functionality to get
feedback from users. Advantage: Users have something concrete
to review.Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 26
Phase 3: Designing the System
Other design approaches Computer-Aided Software
Engineering (CASE) Used for complex systems Automates documenting entity relationships
and data flow Includes project management features, data
dictionaries, documentation support, and graphical output support
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Phase 3: Designing the System
Phase 4: Implementing the System
Deciding whether to build or buy Develop in-house
Allows customization Is often more expensive
Purchase from outside vendor Purchase off the shelf and customize Outsource for specialized system creation
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Phase 4: Implementing the System
Developing the software A subset of the systems development
Testing Acceptance testing is performed by
the users and ensures that the system works properly.
Application testing involves assessing the programs separately and as a group.
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Phase 4: Implementing the System
Training Converting systems
Parallel conversion Pilot conversion Phased conversion Direct (crash) conversion
The fully tested system is the deliverable for phase 4.
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Phase 5: Maintaining the System
Perform postimplementation system review. Evaluates whether the goals of the
system have been met Must meet the needs of the users. Must function properly.
Serves as the phase 5 deliverable
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Summary
Systems analysts work with users and management to develop a system.
A system is a group of interrelated components that accomplish a goal. A system requires modification over time.
The SDLC provides structure to the development of the goal.Copyright © 2011 Pearson Education, Inc. Publishing as Prentice
Hall 32
Summary
The five phases of the system development life cycle are:
Planning the system Analyzing and documenting the
existing information system Designing the system Implementing the system Maintaining the system
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Summary
Lack of user involvement, poor project management, and lack of documentation cause projects to fail.
The SDLC phases should be completed in order with the results of one phase becoming the starting point for the next phase of the cycle.Copyright © 2011 Pearson Education, Inc. Publishing as Prentice
Hall 34
Summary
Deliverables from each phase of the SDLC are input to the next phase:1. Project proposal2. Review of the present information
system3. Review of the proposed information
system4. Fully tested finished result5. System evaluation after its
implementation Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 35
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