CIS 321—IS Analysis & Design Chapter 2: Approaches to System Development

Overview Systems development can be very complex. The systems development ______ cycle (SDLC) framework can help address this complexity. Other aids in systems development are methodologies models tools _________ Two major approaches to systems development: traditional object-oriented

The Basic SDLC Project definition: System development project A planned endeavor with a beginning and an end that produces a desired result System development project The result is an information system A complex project requires a detailed plan Five phases of system development project planning—initiate, plan, obtain approval analysis—determine requirements design—define the solution implementation—implement the solution support—maintain and enhance the system

Project Planning Phase Define the problem existing system proposed system Produce the project _________ establish milestones Confirm project _________ economic, organizational, technical, resource, schedule Staff the project select/acquire the staff and allocate time Launch the project management approval, allocation of resources

Analysis Phase Gather information Define system requirements learn about the problem _________, users, stakeholders Define system requirements draw diagrams Build ___________ of system components to discover additional requirements Prioritize requirements Generate and evaluate alternatives develop in-______, buy a package, contract w/ third party Review recommendations with management choose alternative, proceed

Design Phase Design and integrate the network hardware, operating systems Design the application architecture addresses problem domain requirements Design the user __________ forms, reports, screens, etc. Design the system interfaces communicating with other systems Design and integrate the database Prototype for design details prototypes can be saved for the final system Design and integrate the system controls (security)

Implementation Phase Construct software components Verify and test using VB .NET, Java, etc. Verify and test all possible situations Convert data populate the database Train users and document the system avoid frustrated users Install the system prototype, parallel systems, complete changeover

Support Phase Debug the system Upgrade the system Enhance the system corrective maintenance Upgrade the system _________ maintenance Enhance the system Support the users help desk

SDLC & the Element of Time Waterfall approach each phase is completed before the next one begins Overlapping of phases speed development, required by the nature of the problem _________ of phases perform the same phase repeatedly until it’s good enough to begin the next phase each iteration of one phase provides new information about the previous phase Divide project into miniprojects (UI, apps, DB) ____________ development deliver part of the system before the whole system

Aids for Completing the SDLC Methodologies a collection of techniques for how to use tools to create models Models A model is an ___________ of something in the real world Models can be physical, mathematical, graphical, textual Flowchart, DFD, ERD, structure chart, use case diagram, … Project planning models (PERT and Gantt charts) Tools software support to create models or even program code Techniques step-by-step instructions

Traditional Approach to System Development Structured programming Three structures: sequence, selection, __________ top-down programming (modular programming) Structured design modules arranged in a structure chart modules are loosely coupled and highly __________ Structured analysis data flow diagram (DFD) entity-relationship diagram (ERD) Information engineering (James Martin) rigid focus on strategic planning, data, CASE

Object-oriented System Development (OOSD) A thing that encapsulates attributes and behavior OO analysis identifying problem domain objects and their relationships OO design identifying system objects (people, devices) OO programming C++, Java, C# A class is a specification of one type of object OOSD is more natural, leads to reuse (?)

SDLC Variations Variations of names for phases planning, feasibility study, investigation, strategy planning construction, transition, implementation Variations based on _______-computer interaction sociotechnical systems Multiview soft systems methodology Variations based on speed of development _______ application development (RAD) prototyping

Current Trends in Development 1 Spiral model highly iterative create series of prototypes begin with areas of greatest risk eXtreme Programming (XP) developed by Kent Beck user ________ series of releases two programmers work together work only ____ hours per week

Current Trends in Development 2 Unified Process (UP) developed by Booch, Rumbaugh, Jacobson of _________ Software designed for OOSD uses UML (________ Modeling Language) phases: inception, elaboration, construction, transition Agile Modeling developed by Scott Ambler mix between the lightweight XP and the heavy duty UP iterative and incremental teamwork simplicity validation