1. Data and Process Modeling
Chapter 5
Data and Process Modeling

2. Chapter Objectives
Describe software trends, including the concept of software as a service
Explain software acquisition alternatives, including traditional versus Web-based software development strategies
Describe software outsourcing options, including the role of service providers
Explain advantages and disadvantages of developing software in-house versus other alternatives 3

3. Chapter Objectives
Explain cost-benefit analysis and financial analysis tools
Explain the differences between a request for proposal (RFP) and a request for quotation (RFQ)
Describe the contents of the system requirements document 3

4. Chapter Objectives
Explain the transition from systems analysis to systems design, and the difference between logical and physical design
Explain the transition to systems design and the importance of prototyping
Discuss guidelines for system design, and explain the importance of codes

5. Introduction
Chapter 5 describes the remaining activities in the systems analysis phase
The chapter also describes the transition to systems design, prototyping, design guidelines, and using codes to represent values and simplify data entry 4

6. Development Strategies Overview
Selecting the best development path is an important decision that requires companies to consider three key issues
Web-based software trends
Software outsourcing options
In-house software development alternatives

7. Systems Development Traditional Development Web-based development
Legacy issues of compatibility
Web considered the platform
Local and wide area networks
Web issues are considered enhancements
Scalability issues
Easily scaleable
Can be acquired as a service (packaged systems)
Requires middleware to talk to legacy systems

8. Web-Based Software Trends
The Changing Software Marketplace
In the traditional model, software vendors develop and sell application packages to customers
In addition to traditional vendors, the marketplace now includes many forms of outsourcing, including application service providers (ASP) and firms that offer Internet business services

9. Software Outsourcing Options
Outsourcing is the transfer of information systems development, operation, or maintenance to an outside firm that provides these services, for a fee, on a temporary or long-term basis
Can refer to relatively minor programming tasks or the handling of a company’s entire IT function

10. Software Outsourcing Options
The Growth of Outsourcing
Traditionally, firms outsourced IT tasks as a way of controlling costs and dealing with rapid technological change
Today, outsourcing is a vital business issue that shapes a company’s overall IT strategy
the most important factor is the potential saving in operating costs

11. Software Outsourcing Options
The Growth of Outsourcing
A firm that offers outsourcing solutions is called a service provider
Application service providers (ASP)
Internet business services (IBS)
Also called managed hosting

12. Software Outsourcing Options
Outsourcing Fees
A fixed fee model uses a set fee based on a specified level of service and user support
A subscription model has a variable fee based on the number of users or workstations that have access
A usage model or transaction model charges a variable fee based on the volume of transactions or operations

13. Software Outsourcing Options
Outsourcing Issues and Concerns
Mission-critical IT systems should be out-sourced only if the result is a cost-attractive, reliable, business solution that fits the company’s long-term business strategy
out-sourcing can also affect day-to-day company operations and can raise some concerns

14. Software Outsourcing Options
Outsourcing Issues and Concerns
A company must plan outsourcing carefully to avoid lost revenue, added expenses, and potential litigation
The solution can be only as good as the outsourcing firm that provides the service
Outsourcing can be especially attractive to a company whose volume fluctuates widely
A major disadvantage of outsourcing is that it raises employee concerns about job security

15. In-House Software Development Options
A company can choose to develop its own systems, or purchase, possibly customize, and implement a software package
The most important consideration is total cost of ownership (TCO)
Companies also develop user applications designed around commercial software packages

16. In-House Software Development Options
Make or Buy Decision
The choice between developing versus purchasing software often is called a make or buy, or build or buy decision
The company’s IT department makes, builds, and develops in-house software
A software package is obtained from a vendor or application service provider.

17. In-House Software Development Options
Make or Buy Decision
Companies that develop software for sale are called software vendors
Value-added reseller (VAR)
Vertical application (PkMS)
Horizontal application (MS Money)

18. In-House Software Development Options
Purchasing a Software Package
Lower costs
Requires less time to implement
Proven reliability and performance benchmarks
Requires less technical development staff
Future upgrades provided by the vendor
Input from other companies

19. In-House Software Development Options
Developing Software In-House
Satisfy unique business requirements
Minimize changes in business procedures and policies
Meet constraints of existing systems
Meet constraints of existing technology
Develop internal resources and capabilities

20. In-House Software Development Options
Customizing a Software Package
You can purchase a basic package that vendors will customize to suit your needs
You can negotiate directly with the software vendor to make enhancements to meet your needs by paying for the changes
You can purchase the package and make your own modifications, if this is permissible under the terms of the software license

21. Considerations in make, buy, customize decision
Cost
Time
Skills available
Technology available
Knowledge Base

22. A Software Acquisition Example
Step 1: Evaluate the Information System Requirements
Identify key features
Consider network and web-related issues
Estimate volume and future growth
Specify hardware, software, or personnel constraints
Prepare a request for proposal or quotation
Request for proposal (RFP)
Evaluation model
Request for quotation (RFQ)

23. A Software Acquisition Example
Step 2: Identify Potential Vendors or Outsourcing Options
The Internet is a primary marketplace
Another approach is to work with a consulting firm
Another resource is the Internet bulletin board systems that contains thousands of forums, called newsgroups

24. A Software Acquisition Example
Step 3: Evaluate the Alternatives
Existing users
Application testing
Benchmarks
Match each package against the RFP features and rank the choices

25. A Software Acquisition Example
Step 4: Perform Cost-Benefit Analysis
Identify and calculate TCO for each option you are considering
When you purchase software, what you are buying is a software license
If you purchase a software package, consider a maintenance agreement

26. A Software Acquisition Example
Step 5: Prepare a Recommendation
You should prepare a recommendation that contains your recommendation and lists the alternatives, together with the costs, benefits, advantages, and disadvantages of each option
At this point, you may be required to submit a formal system requirements document and deliver a presentation

27. A Software Acquisition Example
Step 6: Implement the Solution
Implementation tasks will depend on the solution selected
Before the new software becomes operational, you must complete all implementation steps, including loading, configuring, and testing the software; training users; and converting data files to the new system’s format

28. Completion of Systems Analysis Tasks
System Requirements Document
The system requirements document, or software requirements specification, contains the requirements for the new system, describes the alternatives that were considered, and makes a specific recommendation to management
Like a contract
Format and organize it so it is easy to read and use

29. Completion of Systems Analysis Tasks
Presentation to Management
Begin your presentation with a brief overview of the purpose and primary objectives of the system project
Summarize the primary viable alternatives. For each alternative, describe the costs, advantages, and disadvantages

30. Completion of Systems Analysis Tasks
Presentation to Management
Explain why the evaluation and selection team chose the recommended alternative
Allow time for discussion and for questions and answers
Obtain a final decision from management or agree on a timetable for the next step in the process

31. Completion of Systems Analysis Tasks
Presentation to Management
Based on their decision, your next task will be one of the following
Implement an outsourcing alternative
Develop an in-house system
Purchase or customize a software package
Perform additional systems analysis work
Stop all further work

32. The Transition to System Design
If management decides to develop the system in-house, then the transition to the systems design phase begins
Preparing for Systems Design Tasks
It is essential to have an accurate and understandable system requirements document

33. The Transition to System Design
The Relationship between Logical and Physical Design
The logical design defines the functions and features of the system and the relationships among its components
The physical design of an information system is a plan for the actual implementation of the system

34. Systems Design Guidelines
The systems analyst must understand the logical design of the system before beginning the physical design of any one component
Data design
User interface
System design specification

35. Systems Design Guidelines
System Design Objectives
The goal of systems design is to build a system that is effective, reliable, and maintainable
A system is reliable if it adequately handles errors
A system is maintainable if it is well designed, flexible, and developed with future modifications in mind

36. Systems Design Guidelines
System Design Objectives
User considerations
Carefully consider any point where users receive output from, or provide input to, the system
Anticipate future needs of the users, the system, and the organization
Provide flexibility
Parameter, default
Data Considerations
Data should be entered into the system where and when it occurs because delays cause errors
Data should be verified when entered to catch errors immediately

37. Systems Design Guidelines
System Design Objectives
Data Considerations
Automated methods of data entry should be used whenever possible
Access for data entry should be controlled and all entries or changes to critical data values should be reported – audit trails
Every instance of entry and change to data should be logged
Data should be entered into a system only once
Data duplication should be avoided

38. Systems Design Guidelines
System Design Objectives
Architecture considerations
Use a modular design
Design modules that perform a single function are easier to understand, implement, and maintain

39. Prototyping
Prototyping produces an early, rapidly constructed working version of the proposed information system, called a prototype
Prototyping allows users to examine a model that accurately represents system outputs, inputs, interfaces, and processes

40. Prototyping Prototyping Methods System prototyping Design prototyping
Throwaway prototyping

41. Prototyping Prototyping Methods Prototyping offers many benefits
Users and systems developers can avoid misunderstandings
Managers can evaluate a working model more effectively than a paper specification
Also consider potential problems
The rapid pace of development can create quality problems
In very complex systems, the prototype becomes unwieldy and difficult to manage

42. Prototyping Limitations of Prototypes
A prototype is a functioning system, but it is less efficient than a fully developed system
Systems developers can upgrade the prototype into the final information system by adding the necessary capability
Otherwise, the prototype is discarded

43. Using Codes During System Design
Overview of Codes
Because codes often are used to represent data, you encounter them constantly in your everyday life
They save storage space and costs, reduce transmission time, and decrease data entry time
Can reduce data input errors

44. Using Codes During System Design
Types of Codes
Sequence codes
Block sequence codes
Alphabetic codes
Category codes
Abbreviation codes

45. Using Codes During System Design
Types of codes
Significant digit codes
Derivation codes
Cipher codes
Action codes
Self-checking codes

46. Using Codes During System Design
Developing a Code
Keep codes concise
Allow for expansion
Keep codes stable
Make codes unique
Use sortable codes
Avoid confusing codes

47. Using Codes During System Design
Developing a Code
Make codes meaningful
Use a code for a single purpose
Keep codes consistent

48. Chapter Summary
This chapter describes system development strategies, the preparation and presentation of the system requirements document, and the transition to the systems design phase of the SDLC
An important trend that views software as a service, rather than a product, has created new software acquisition options
Systems analysts must consider Web-based development environments 49

49. Chapter Summary
The systems analyst’s role in the software development process depends on the specific development strategy
The most important factor in choosing a development strategy is total cost of ownership (TCO)
The process of acquiring software involves a series of steps 49