Computers Are Your Future Eleventh Edition Chapter 13: Systems Analysis & Design Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall1

Systems Analysis & Design Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall2

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. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall3

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. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall4

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 requirements Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall5

System Analysts: Communication Counts Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall6

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 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall7

The Systems Development Life Cycle Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall8

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 Hall9

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. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall10

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. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall11

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. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall12

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 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall13

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 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall14

Phase 1: Planning the System Recognizing the need for a system may come from acknowledging deficiencies. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall15

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. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall16

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. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall17

Phase 1: Planning the System A Gantt chart summarizes plans Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall18

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) Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall19

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. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall20

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 Hall21

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. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall22

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall23 Design tools Deliverable: Entity-relationship diagram Phase 3: Designing the System

Design tools Data flow diagram uses symbols for data movement Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall24 Phase 3: Designing the System

Design tools Team members develop: Project dictionary: defines terminology Data dictionary: identifies data types Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall25 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 Hall26 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 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall27 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 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall28

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. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall29

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. Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall30

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 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall31

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 Hall32

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 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall33

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 Hall34

Summary Deliverables from each phase of the SDLC are input to the next phase: 1. Project proposal 2. Review of the present information system 3. Review of the proposed information system 4. Fully tested finished result 5. System evaluation after its implementation Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall35