contemporary information systems development
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Contemporary Information Systems Development
Chapter 10
Chapter Objectives
• Explain emerging approaches for collecting and structuring the information needed to design and construct an information system
• Describe prototyping, rapid application development, and object-oriented analysis and design
• Understand how and why to use several automated tools for supporting contemporary development
Contemporary Methods for Collecting and Structuring
System Requirements
• Critical Success Factors (CSF)
• Joint Application Requirements (JAR)/Joint Application Design (JAD)
Critical Success Factors (CSF)
• Something that must go well to ensure success for a manager, department or company
• How the CSF approach works– Select people from a cross-section of the major
functional areas– Ask each person to define his or her own CSF– Merge personal CSF to create set of organization-
wide CSF
Merging Individual CSF to Organizational CSF
Strengths and Weaknesses of the CSF Approach
• Strengths– Understandable by
senior managers– Provides structured
process for collecting information needs of company
• Weaknesses– Can lead to an over-
simplification of a complex situation
– Hard to find analysts to perform the CSF process
– Not user-centered
Joint Application Requirements (JAR)Joint Application Design (JAD)
• Group-based methods for collecting requirements and creating designs
• How the JAD approach works– Held in a conference room or a special-
purpose JAD room– JAD expert facilitator helps group work
effectively– Scribe records jointly agreed-upon design
information
JAD Room
Strengths and Weaknesses of JAD
• Strengths– More people
involved in the effort– Provides greater
acceptance of new system
– Training and support costs significantly lower
• Weaknesses– Difficult to get all
relevant users together
– Inherent group process problems
Contemporary Approaches for Designing and Building Systems
• Prototyping
• Rapid Application Development
• Object-Oriented Analysis and Design
Prototyping
• Uses a “trial-and-error” approach• How Prototyping Works
– Interview users of the system– Develop a prototype of the new system– Share with users – Users preview and ask for changes– Modify the prototype again; share with users– Continue process until users approve the system
The PrototypingProcess
Strengths and Weaknesses of Prototyping
• Strengths– Develops close
working relationship between designer and users
– Best method for systems with hard-to-define specifications
– Works well with other development tools
• Weaknesses– Not appropriate for
every type of system– Sometimes rushes
the development process
Rapid Application Development (RAD)
• How RAD works– Prototyping– Computer-based
development tools– Special management
practices– Close user
involvement
• Four-phased methodology– Requirements
planning– User design– Construction– Move to the new
system
Iterative Refinement of RAD
Strengths and Weaknesses of Rapid Application Development• Strengths
– Has active involvement of users
– Produces a system in a fraction of the time normally needed
• Weaknesses– Can limit systems in
functionality and flexibility for change
– May not be of highest quality
Object-Oriented Analysis and Design (OOA&D)
• Uses object-oriented languages (OOP) with reusable modules
• How OOA&D works– Requirements broken down into smaller and
smaller pieces called “modules”– Modules defined, programmed, and then
pieced together to create the system– Has a tight coupling between data and the
operations performed on them
Strengths and Weaknesses of OOA&D
• Strengths– Forces designers to
integrate their thinking
– Can improve quality – Can reduce
development time– Objects can be
reused by other systems
• Weaknesses– Needs retraining of
existing analysts and programmers
– No research to support claim of higher quality or reduced time
– Many programmers do not search for reusable code
Tools for Supporting Contemporary Systems
Development
• Computer Aided Software Engineering (CASE)
• Group Support Systems
• Advanced Programming Languages
Computer Aided Software Engineering (CASE)
• Automated software tools used to develop information systems
• Upper CASE – Used to automate the first three phases of
SDLC
• Lower CASE – Used to automate the last two phases of
SDLC
High-level DFD
Lower-level DFD
General Types of CASE Tools
• Diagramming tools
• Screen and report generators
• Analysis tools
• Repository
• Documentation generators
• Code generators
Group Support Systems
• GSS technology used to structure and coordinate group processes
• GSS + JAD = Electronic JAD (E-JAD)– Using GSS software to support JAR / JAD
activities
Advanced Programming Languages
• Visual Programming– Allows developers to quickly build new user
interfaces, reports, and other features
• Object Oriented Programming (OOP)– Creates reusable objects
• Fourth-Generation Languages and Beyond– Allows users to request information with easy to
use syntax
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