CASE Tools

1
CASE Tools

• Computer-Aided Systems Engineering
• To support each phase of the system development
  life cycle with a set of laborsaving tools.
• CASE tools are programs (software) that automate
  or support one or more phases of a systems
  development life cycle.
• Intended to accelerate the process of developing
  systems and to improve the quality of the
  resulting systems..
• CASE is not a methodology or an alternative to
  methodologies.
• CASE is an enabling technology that supports a
  methodologys preferred strategies, techniques,
  and deliverables.

2
Why CASE?

• Increasing costs of software development due to
  the extreme intensive labor required.
• System development is often conducted in an ad
  hoc fashion.
• Avoid simple human errors in software
  development.
• CASE offers an important opportunity to alleviate
  the problems of application development and
  maintenance that can have catastrophic
  consequences.

3
CASE Tool Classification

• Upper-CASE describes tools that automate or
  support the upper or earliest phases of systems
  development
• Lower-CASE describes tools that automate or
  support the lower or later phases of systems
  development
• I-CASE (integrative case) support the entire SDLC

4
CASE Objectives

• Create development process standards
• Improve overall application quality
• Decrease design time and improve time to market
• Decrease required effort and time in application
  testing
• Encourage integration of development projects
• Improve effectiveness of project management
  activities
• Decrease required effort and time in application
  maintenance activities
• Promote organization-wide reusable program code
• Improve portability of applications across
  platforms and operating environments

5
The Good and Bad News about CASE

• Development process productivity and quality
  increases are realizable
• Portability of new systems to other platforms is
  greatly enhanced
• Analyst skill set will improve due to greater
  understanding of the process
• Time to delivery of new applications will
  decrease
• Conformity to development standards will increase

• CASE acquisition costs are extremely high
• Training of analysts and administrators is costly
  and time-consuming
• Most organizations do not have clear standards
  for application development
• CASE tools can be viewed as a threat to job
  security
• CASE tools do not have a great reputation due to
  early benefits not being realized

6
CASE Tool Repository

• Heart of CASE tool is the central repository
• Stores all the information to analyze, create,
  design and modify an application from feasibility
  to implementation and maintenance

7
CASE Tool Components
8
Modeling and Diagramming Tools

• Support logical model development (data and
  process)
• Process Modeler
• can be used to develop a diagram which
  illustrates the activities within an organization
  system and the sequence in which they take place.
• Function Hierarchy Diagrammer
• facilitates the modeling of the hierarchies of
  all the functions that are performed by a
  business and can assist in identifying which
  parts of the business are currently, or can be
  automated.
• Data Flow Diagramming Tools
• Entity Relationship Diagramming Tools
• Not just drawing packages!

9
Prototyping and Transformation Tools

• Enable the rapid conversion of analysis
  requirements into default database and
  application designs.
• Application transformers
• The application transformers create a first-cut
  application design based on an existing database
  design and on the functions and business rules
  placed in the repository during detailed
  analysis.
• Database Transformers
• The database transformer creates and maintains
  database designs based on entity models recorded
  in the central repository.
• Reverse-engineering
• Form and Report Generators
• Automate the activities necessary for the
  analyst to design how the various users will
  interact with the system.

10
Documentation and Code Generators

• The documentation generators generate
  phase-specific documentation from the data in the
  central repository.
• Code generators produce high-level code from the
  various diagrams, models, forms, reports, and
  data definitions contained with the central
  repository.
• Reverse Engineering and Reengineering
• Reverse engineering function allows for the
  generation of design specifications and models
  from existing program code and data structures.
• Reengineering functions are advanced reverse
  engineering modules that provide a certain level
  of automation to the redesign process and make
  recommendations as to the logic of a program.

11
JAD Joint Application Development

• Pros
• Improve the quality of the information gathering
  activities while managing the time and resources
  necessary to gather the information in a more
  efficient manner.
• Enhance the development of a shared understanding
  among the system stakeholders with regard to what
  the system is intended to do and for whom.
• Improve end user motivation and performance

• Cons
• Require extreme commitment of a large number of
  employees and technical personnel for several
  days at a time.
• The number of participants in a typical JAD
  session is necessarily limited for the sake of
  practicality and coordination.
• Require professional diplomacy and communication
  skills.

12
RAD Rapid Application Development

• RAD promises the ability to develop and deploy a
  system more quickly while maintaining quality and
  reducing development costs.
• a series of iterative work sessions intended to
  create a prototype.
• Primary RAD application development techniques
• Use of iterative prototypes, CASE, and JAD
  sessions
• Adopt timeboxed approach to development
• imposing an immovable deadline on the completion
  of a task, activity, stage, or system by strictly
  controlling functionality
• Major differences between the traditional SDLC
  and RAD
• The imposition of timeboxes in RAD
• The upfront, and often labor intensive,
  activities of the SDLC are condensed through
  parallel actions, the use of JAD, and intensive
  iterative prototyping.

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RAD vs. SDLC
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RAD Activities and Deliverables
15
RAD Pros and Cons

• Time savings in overall project phases are
  realizable.
• RAD reduces overall project costs and human
  resource requirements.
• Works well with development efforts where time is
  of the essence.
• System design changes can be affected much more
  rapidly than with the traditional SDLC approach.
• The user perspective is represented in the final
  system with regard to both functionality and
  interface.
• Creates a strong sense of ownership among all
  project stakeholders.

• Focus on time to delivery and project cost may
  result in lower system functionality and overall
  quality.
• RAD leaves little time to focus on the overall
  business environment and the expected changes
  both near and far term.
• Less consistency and integration with other
  organizational systems.
• Documentation quality and conformity to existing
  development standards is often decreased.
• System scalability becomes more difficult.
• Requires an extremely high commitment of human
  resources during the early stages.