Prototyping Environment
Requirements for rapid
application development
Prototyping
“It is easier to tell what you don’t like
about an existing system than to describe
what you would like in an imaginary one”
A.M. Jenkins, 1983
Tactic
Evolution
Throwaway
Life Cycle component
The Prototyping Process
Identify
Initial
Requirements
Develop
System
Use and
Evaluate
Document and Install
Iterate
Roles
User
Intermediary
Builder
Technical
Support
Toolsmith
Responsible for business
solutions
Run system for user
Write code for application
Supports the development
tools
Build basic tool modules (often
work for software houses)
Choice
Life Cycle
 Prespecification
possible
 Changes expensive
 Good project
communication
 Static model OK
 Rigorous approach
useful
 Iteration unacceptable
Prototype
 Prespecification
difficult
 Quick tools work
 Communications gap
 Animated model
needed
 Rigor after
requirements
 Iteration accepted
Factors Favoring
Prototyping
Structure: interactive, on-line (OLAP)
Logic: structured but not algorithmic
DSS applications are often data-report types
User: competent and active participant
Time Constraint: not a crash project
Management: willing to work with method
Size: not overly large or complex
Factors Favoring
Prototyping
Problem:
imprecise specifications,
poorly defined communications,
interactive model needed
Why not use prototyping
Builders Added Value
(Professional Design)
Date and time stamps
Control totals
Audit trails
Common interface feel
Additional functions
Testing
Prototyping Tactics
Normalize data to 3NF
Use component engineering
Use existing components
Assemble from existing parts
Reuse pieces
Create pieces so that they can be reused
Cut and paste
Keep a set of examples
Prototyping Tactics
Use active data dictionaries
Automate documentation
Keep teams small
Integrated software workbench tools
Specify objectives not procedures
Provide end-user report writing tools
Use professional prototypers
Have systems developers work with
prototypers
Project Management
Initial Model: 2-6 weeks
Must be fast enough to maintain interest
Revisions: immediate - 2 weeks
Chargeback: use charges to avoid frivolous
changes
Approval: determine the group who approves
iterations
Sign off: formal acceptance