case tools_ppt.ppt

7/29/2019 CASE Tools_PPT.ppt

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RAD & CASE TOOLS

Rapid Application Development

CASE Tools

Types of CASE Tools

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RAPID APPLICATIONS DEVELOPMENT (RAD)

Systems development methodology createdto radically decrease the time needed todesign and implement information systemsradically.

Five key factors1. Extensive user involvement

2. Joint Application Design sessions

3. Prototyping

4. Integrated CASE tools

5. Code generators

19.2


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RAPID APPLICATION DEVELOPMENT

3

Object-oriented approach to systems development

Method of development + Software tools

Commonly, a rapid application development (RAD) is implemented in

three phases:


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RAD DEVELOPMENTCYCLE


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THE PROCESSOF DEVELOPINGAN

APPLICATION RAPIDLY

RAD is a general strategy rather than asingle methodology

Goals To analyze a business process rapidly To design a viable system solution through

intense cooperation between users anddevelopers

To get the finished application into the hands ofthe users quickly

Traditional SDLC steps are followed, but

phases are combined Iteration is limited to design and

development phases


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COMPONENTSOF RAD

User involvement is key to success

Prototyping is conducted in sessions similar to Joint

Application Design (JAD)

Prototyping screens become screens within theproduction system

CASE tools are used to design the prototypes


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APPROACHESTO RAD

Martins RAD Life Cycle Systems requirement determination is done in context

of a discussion of business problems and businessareas

User Design End users and IS professionals participate in JAD workshops CASE tools are used to support prototyping

Construction Designer creates code using code generator

End user validates screens and other aspects of design

Cutover New system is delivered to end users


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RAD SUCCESS STORIES

Inprise/Borlands Delphi U.S. Navy Fleet Modernization

Requirements

Move from three character-based systems to a unified, GUI-

based system based on a single databaseReasons for choosing Delphi

Support for rapid prototyping

Promise of re-use of components

Outcome

System developed in 6 months Estimated development savings of 50 percent

New system resulted in immediate 20 percent savings due toreduced maintenance costs


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RAD SUCCESS STORIES

Inprise/Borlands Delphi (continued)

First National Bank of Chicago

Electronic Federal Tax Payment System

Delphi enabled rapid prototyping anddevelopment

10 months of development time

125 programmers

250 million rows of data and 55 gigabytes of dataon-line


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RAD SUCCESS STORIES

VisualAge for Java Comdata

Modular Over the Road System (MOTRS)

IBM Global Services chosen as vendor

Servlets Programming modules that expand the functions of the Web

server

Applets Embedded code run from client browser

Nine months to completion

Three months of research Three months of coding

Three months of testing


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RAD is a team-based technique that speeds upinformation systems developments.

Like JAD, RAD uses a group approach, but goesmuch further.

RAD resembles a condensed version of the entire

SDLC, with users involved every step of the way.

RAPID APPLICATION DEVELOPMENT


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Requirement planning Users, managers, and IT staffs agree upon business

needs, project scope and system requirements

User Design

Interact with users, build models and prototypes, andconduct intensive JAD-type sessions

Construction Program and application development, coding, integration

and system testing

Cutover Data conversion, full scale testing, system changeover,

user training

RAD PHASESAND ACTIVITIES


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RAD Phases and Activities


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Kendall&Kendall

200

5

Pear

son

Pren

tice

Hall

6-14

RADANDTHE SDLC

RAD tools are used to generate screens and exhibitthe overall flow of the application.

Users approve the design and sign off on the visualmodel.

Implementation is less stressful because usershelped to design the business aspects of thesystem.


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Kendall&Kendall

200

5

Pear

son

Pren

tice

Hall

6-15

WHENTO USE RAD

RAD is used when:

The team includes programmers and analysts who areexperienced with it.

There are pressing reasons for speeding up application

development. The project involves a novel ecommerce application and

needs quick results.

Users are sophisticated and highly engaged with thegoals of the company.


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PROTOTYPING

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It can be defined as an interactive process for systems developmentinwhich users and analysts are in close collaboration for converting

requirements to a working system that is continuously revised.

Prototyping can be used as:

Alternative to the traditional SDLC approach

Technique for gathering information in the requirements analysis phase of the

SDLC (help to find what the user really wants)

Prototyping does not mean quick and unplanned implementation!


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PROTOTYPING

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Prototyping is a complex technique and to apply it successfully, detailedknowledge of the SDLC is required.

Prototyping helps to set priorities and adapt the planning to changes in

requirements with minimum disruption.

Users play a crucial rolein prototyping, hence:

Encourage and welcome user input

No resistance to changing the prototype

Two main purposes for prototyping:

Know users reaction to working with prototype Assess how well the prototypes features address the users requirements


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PROTOTYPING

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Guidelines for developing prototypes:

Work in manageable modules

Modify in successive iterations

Estimate the costs of building the prototype

Build the prototype rapidly

Stress the user interface

Types of Prototypes

Patched-up prototype all necessary features but inefficient.

Non operational prototype only input/output are prototyped.

First-of-a-series prototype first full-scale model or pilot.

Selected features prototype operational model with some of the features

in a module.


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PROTOTYPING

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Advantages of prototypes:

Potential for changes to the system early in the development.

Opportunity to stop developing a non-working system.

Possibility of developing system that closely addresses users requirements

and expectations.

Disadvantages of prototypes:

Prototyping is difficult to manage.

Increase cost


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CASE TOOLS

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Computer-Aided Software Engineering (CASE) tools are automatedsoftware packages that help to automate activities in the SDLC.

CASE tools aim to enforce an engineering-type approach to the

development of software systems.

CASE tools range from simple diagramming tools to verysophisticated programs to document and automate most of the

stages in the SDLC.

CASE tools used since the early 1990s


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COMPONENTSOF CASE

CASE

repositoryDocument

Generator

DesignGenerator

Analysistool

Code

Generator

Drawing

Tool

Error-checking

tool

Security and

Version Control

Screen and

Report Generator

Prototyping

Tool

Database

Generator


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CASE VS. TRADITIONAL SYSTEMS DEVELOPMENT

Traditional Systems Development

Emphasis on coding and testing Paper-based specifications Manual coding of programs Manual documenting

Intensive software testing Maintain code and documentation

CASE-Based SystemsDevelopment

Emphasis on analysis and design Rapid interactive prototyping Automated code generation Automated documentation generation Automated design checking Maintain design specifications


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CASE TOOLS

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The case for using CASE tools:

Improve quality of systems developed.

Help to increase the productivity of systems analysts.

Improve communication within the development team and with

users. Encourage an integrated approach to the SDLC.

Improve the management of the project.

Particularly helpful for systems maintenance.


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CASE TOOLS

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And more specifically:

Faster creation/modification of documentation.

Documents can easily be distributed and reviewed.

Reduction in the amount of paperwork.

Maintain a record of the SDLC in an effective way. Members of the development team can interact more easily

throughout the project.

Communication with the user is improved because changes can be

reported, implemented and revised more quickly.

Interrelation and continuity between stages in the SDLC are easier to

identify and verify.

Crucial for RAD, XP and similar methodologies.


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CASE TOOLS

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Potential drawbacks of CASE Tools:

Lack of standards among different CASE tools.

Development should be driven by the analyst and not by the CASE tools.

CASE tools are no substitute for human expertise.


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TYPESOF CASE TOOLS

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There are three types of CASE tools:

Upper CASE

Support analysis and design

Lower CASE

Support programming and implementation

Integrated CASE

Combines both upper and lower CASE


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TYPESOF CASE TOOLS

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Upper CASE tools

Create and modify the system design.

Information about the project stored in the CASE repository (reports,

diagrams, files)

Support modelling of how the system fits into the organisation. Analysis reports show incomplete parts and errors in the system design

e.g. balance between process and data models.

Lower CASE Tools

Generate source code and reduce need for systems programming.

Time for maintenance is reduced because test and debug are eliminated.

Once mastered, promote the re-use of existing documentation and

components.


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TYPESOF CASE TOOLS

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Examples of CASE Tools:

Diagramming for representing processes, data and control structures

graphically. (analysis)

CASE repository holds information required to create, modify and

evolve the system. (analysis, design, implementation)

Form and report generators automate generation of forms and

reports to aid prototyping. (design, implementation, RAD, XP)

Code generators automate generation of source code from diagrams

and forms. (design, implementation)


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TYPESOF CASE TOOLS

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Examples of CASE Tools (cont.):

Project management aid in the planning, tracking, controlling and

reporting of project management. (planning)

Document generator create standard reports based upon the

contents of the CASE repository. (analysis, design, implementation)

CASE analysis tools help to identify problems of inconsistency,

redundancy, and omissions. (more likely in analysis and design)