Prototyping Environment Requirements for rapid application development Prototyping

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 z. Evolution z. Throwaway z. Life Cycle component

The Prototyping Process Identify Initial Requirements Develop System Use and Evaluate Document and Install Iterate

Roles z User z Intermediary z Builder z Technical Support z 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 z Prespecification possible z Changes expensive z Good project communication z Static model OK z Rigorous approach useful z Iteration unacceptable Prototype z Prespecification difficult z Quick tools work z Communications gap z Animated model needed z Rigor after requirements z Iteration accepted

Factors Favoring Prototyping z Structure: interactive, on-line (OLAP) z Logic: structured but not algorithmic DSS applications are often data-report types z User: competent and active participant z Time Constraint: not a crash project z Management: willing to work with method z Size: not overly large or complex

Factors Favoring Prototyping z Problem: imprecise specifications, poorly defined communications, interactive model needed Why not use prototyping

Builders Added Value (Professional Design) z. Date and time stamps z. Control totals z. Audit trails z. Common interface feel z. Additional functions z. Testing

Prototyping Tactics z Normalize data to 3 NF z Use component engineering Use existing components Assemble from existing parts Reuse pieces Create pieces so that they can be reused z. Cut and paste z Keep a set of examples

Prototyping Tactics z Use active data dictionaries z Automate documentation z Keep teams small z Integrated software workbench tools z Specify objectives not procedures z Provide end-user report writing tools z Use professional prototypers z Have systems developers work with prototypers

Project Management z Initial Model: 2 -6 weeks Must be fast enough to maintain interest z Revisions: immediate - 2 weeks z Chargeback: use charges to avoid frivolous changes z Approval: determine the group who approves iterations z Sign off: formal acceptance