1. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 7 - 1 Systems Analysis and Design, 2 nd Edition Alan Dennis and Barbara Haley Wixom John Wiley & Sons, Inc. Slides by Roberta M. Roth University of Northern Iowa

2. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 7 - 2 System Design Chapter 8

3. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 3 Key Definitions Design phase Decide how to build the system Create system requirements that describe technical details for building the system System specification Final deliverable from design phase Conveys exactly what system the design team will implement during the implementation phase

4. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 4 Design Phase Steps Present design alternatives (make, buy, or outsource) Convert logical process and data models into physical models Design the architecture for the system Make hardware and software selections Design the system inputs and outputs Design the way data will be stored Design the programs for the underlying processes Create the system specification

5. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 5 Classical Design Mistakes Reducing design time Feature creep Silver bullet syndrome Switching tools in mid-project

6. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 7 - 6 DESIGN STRATEGIES

7. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 7 Design Strategies Custom development (build from scratch) in-house Purchase software package (and customize it) Outsource development to third party

8. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 8 Custom Development ProsCons Allows flexibility and creativity Consistent with existing technology and standards Builds technical skills and functional knowledge in-house Requires significant time and effort May exacerbate existing backlogs May require missing skills Often costs more Often takes more calendar time Risk of project failure

9. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 9 Packaged Software Available for many common business needs Tested, proven; cost and time savings Rarely a perfect fit with business needs May allow for customization Manipulation of system parameters Changing way features work Synchronizing with other application interfaces May require workarounds

10. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 10 Systems Integration Building systems by combining packages, legacy systems, and custom pieces Integrating data is the key

11. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 11 Outsourcing Hiring an external vendor, developer, or service provider May reduce costs or add value Risks include possibly Losing confidential information Losing control over future development Losing learning opportunities

12. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 12 Outsourcing Contracts Time and arrangements Fixed-price Value-added

13. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 13 Outsourcing Guidelines Keep lines of communication open Define and stabilize requirements before signing the contract View the relationship as a partnership Select vendor, developer, or provider carefully Assign someone to manage the relationship Don’t outsource what you don’t understand Emphasize flexible requirements, long-term relationships, and short-term contracts

14. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 7 - 14 DESIGN STRATEGY

15. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 15 Selecting a Design Strategy Consider each of the following when deciding what strategy to use: Business need In-house experience Project skills Project management Time frame

16. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 16 Selecting a Design Strategy Custom DevelopmentPackaged SystemOutsourcing Business needThe business need is unique The business need is common The business need is not core to the business In-house experience In-house functional and technical experience exists In-house functional experience exists In-house functional or technical experience does not exist Project skillsDesire to build in- house skills Skills are not strategic Outsourcing is a strategic decision Project management Have highly skilled project manager and proven methodology Project manager can coordinate vendor’s efforts Highly skilled project manager at appropriate organizational level Time frameTime frame is flexibleTime frame is shortTime frame is short or flexible

17. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 7 - 17 SELECTING A DESIGN STRATEGY

18. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 18 Developing an Alternative Matrix What tools and technologies are needed for a custom development project? What vendors make products that address the project needs? What service providers would be able to build this application if outsourced?

19. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 19 Developing an Alternative Matrix Combine several feasibility analyses into one matrix Include technical, budget, and organizational feasibilities Assign weights to indicate the relative importance of the criteria Assign scores to indicate how well the alternative meets the criteria

20. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 20 Developing an Alternative Matrix

21. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 21 Request for Proposals (RFP) Solicits proposals from vendor, developer, or service provider Explains the system to be built and criteria for selecting among applicants Request for Information (RFI) -- a shorter and less detailed version

22. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 22 Request for Proposal Contents Description of desired system Special technical needs or circumstances Evaluation criteria Instructions on how to respond Desired schedule Other information that will help the submitter to make a more complete or accurate proposal

23. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 23 Your Turn If your university were investing in an on- line registration system, would you recommend -- Building it in-house? Buying a package? Outsourcing the project? What is the basis for your recommendation?

24. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 7 - 24 MOVING FROM LOGICAL TO PHYSICAL MODELS

25. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 25 Key Definitions Physical process models and physical data models Show the implementation details and explain how the system will work, including Actual, specific technology Format of information Human interaction with system CRUD (create, read, update, delete) matrix Technique to ensure that the data stores are associated with the right processes

26. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 26 The Physical DFD Contains the same components as the logical DFD The same rules pertaining to balance and decomposition apply Contains additional details describing how the system will be built

27. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 27 Steps to Create the Physical DFD Add implementation references Draw a human-machine boundary Add system-related data stores, data flows and processes Update data elements in the data flows Update the metadata in the CASE repository

28. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 28 Contrasting Logical and Physical DFDs A Logical DFD A Physical DFD

29. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 29 The Physical ERD Contains the same components as the logical ERD The same rules pertaining to cardinality and modality apply Contains additional details describing how the data will be stored, in a file or database table Additional metadata content required

30. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 30 Steps to Create the Physical ERD Change entities to tables or files Change attributes to fields Add primary keys Add foreign keys Add system-related components

31. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 31 Metadata Entries for a Field

32. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 32 The CRUD Matrix Technique to balance the physical process and data models with each other Process 1Process 2Process 3Process 4 Data Store A CRUDR Data Store B R Data Store C RCRUR Data Store D CRUD

33. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 33 Summary The design phase is where the blueprint of the system is developed Design strategy is considered and selected from: custom application development, buying a package and customizing it, and outsourcing. Physical DFDs and ERDs add details about the implementation of the system to the “business view” The system specification compiles all the design phase deliverables to be used by the system builders

34. PowerPoint Presentation for Dennis & Haley Wixom, Systems Analysis and Design, 2 nd Edition Copyright 2003 © John Wiley & Sons, Inc. All rights reserved. 8 - 34 Copyright © 2003 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in Section 117 of the 1976 United States Copyright Act without the express written permission of the copyright owner is unlawful. Request for further information should be addressed to the Permissions Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for redistribution or resale. The Publisher assumes no responsibility for errors, omissions, or damages, caused by the use of these programs or from the use of the information contained herein.