information system applications
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INFORMATION SYSTEM APPLICATIONS. System Development Life Cycle. PRIMARY OBJECTIVES. Explain the phases in the system development life cycle Identify the guidelines for system development - PowerPoint PPT PresentationTRANSCRIPT
INFORMATION SYSTEM APPLICATIONS
System Development Life Cycle
PRIMARY OBJECTIVES
Explain the phases in the system development life cycle
Identify the guidelines for system development
Discuss the importance of project management, feasibility assessment, information gathering techniques and documentation
PRIMARY OBJECTIVES (cont.) Describe how structured tools such as
data flow diagrams and entity-relationship diagrams are used in analysis and design
Identify program development as part of the system development life cycle
WHAT IS THE SYSTEM DEVELOPMENT LIFE
CYCLE?
Organized set of activities used to guide those involved through the development of an information system
Phases in the system development life cycle (SDLC) Planning Analysis Design Implementation Support
System Life Cycle
System Study Design
Programming
InstallationEvaluate+Maintenance
Project definition
Who participates in the system development life cycle? Project team Users Information systems personnel Systems analyst Programmers Steering committee
Project management
Scope Project plan Gantt chart
Feasibility assessment
Operational feasibility Will the system work in their environment? Schedule feasibility Are project deadlines reasonable? Technical feasibility Do they have the resources to support the system –
people, hardware, software? Economic feasibility Does it make economic sense?
Documentation
Project notebook - entire collection of documentation
Project dictionary - an automated project notebook
Data and information gathering techniques Reviewing current system documentation Observation Questionnaires Interviews Joint-application design (JAD) sessions Researching
Analysis Phase
Activities/Tasks: Fact Gathering Data Flow Diagrams (DFD) : Used to
document the flow of information through an information system and identify problem areas.
Analysis Phase
Activities/Tasks: Process Description: Used to define
the internal workings of a process on the DFD.
Data Dictionary : Used to document the data definitions and formats.
Analysis Phase
Activities/Tasks: Data Modeling: Designing the necessary databases
and specifying how they may be accessed. System Modeling: Using requirements to create
actual plans for the new information system. Project Management: The process of controlling the
project to ensure schedules are met, estimates are updated, and costs are contained.
Detailed Analysis
Study the current system Identify the users’ wants, needs, and
requirements Present alternative solutions
Detailed Analysis
Structured Analysis and Design Tools– Data Flow Diagrams– Structured Analysis (HIPO charts)– Work Break Down Structure– Entity Relationship Diagrams– Decision Tables– Decision Trees– Data Dictionary
Design phase activities
Covert DFDs into structure charts (Hierarchical diagram of program modules)
User Interface design (Input/Output)– Forms
Data base design Structured walkthroughs Design Testing Procedures
Detailed Design of Software Database design
– Data store in DFD – Logical modeling (ER - diagrams)– Normalization (Data redundancy & integrity)
Data security Program Design
– Program Specification package– System Flowchart
Detailed Design of Software
CASE tools Computer-aided software engineering (CASE)
Graphics Prototyping Quality assurance Code generators
Detailed Design
Quality review
Necessary to double-check assumptions and design
Structured walkthrough
IMPLEMENTATION PHASE – SDLC #4
Develop programs Install and test the new system
Train and educate users
Convert to the new system
Develop programs
Program development life cycle (PDLC) – Analyze – Design the programs – Code – Test the programs – Maintain the programs
Implementation Phase
Install and test the new system
System test - verify that all programs work and work together
Integration test - verify that an application works with other application in the system
Acceptance test - performed by users with real data Types of testing varies
IMPLEMENTATION PHASE – SDLC #4
Train and educate users
– Classroom-style lectures – One-on-one sessions – User manuals – CAI
IMPLEMENTATION PHASE – SDLC #4
Convert to the new system Direct Parallel Phased Pilot conversion
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SUPPORT PHASE – SDLC #5
Conduct post-implementation system review
Identify errors Identify enhancements Monitor performance
Questions and comments?