INFORMATION SYSTEM APPLICATIONS System Development Life Cycle

PRIMARY OBJECTIVES n Explain the phases in the system development life cycle n Identify the guidelines for system development n Discuss the importance of project management, feasibility assessment, information gathering techniques and documentation

PRIMARY OBJECTIVES (cont.) n Describe how structured tools such as data flow diagrams and entity- relationship diagrams are used in analysis and design n Identify program development as part of the system development life cycle

WHAT IS THE SYSTEM DEVELOPMENT LIFE CYCLE ? n Organized set of activities used to guide those involved through the development of an information system

Phases in the system development life cycle (SDLC) n Planning n Analysis n Design n Implementation n Support

System Life Cycle System Study Design Programming Installation Evaluate+ Maintenance Project definition

Who participates in the system development life cycle? n Project team n Users n Information systems personnel n Systems analyst n Programmers n Steering committee

Project management n Scope n Project plan n Gantt chart

Feasibility assessment n Operational feasibility n Will the system work in their environment? n Schedule feasibility n Are project deadlines reasonable? n Technical feasibility n Do they have the resources to support the system – people, hardware, software? n Economic feasibility n Does it make economic sense?

Documentation n Project notebook - entire collection of documentation n Project dictionary - an automated project notebook

Data and information gathering techniques n Reviewing current system documentation n Observation n Questionnaires n Interviews n Joint-application design (JAD) sessions n Researching

Analysis Phase n Activities/Tasks: n Fact Gathering n Data Flow Diagrams (DFD) : Used to document the flow of information through an information system and identify problem areas.

Analysis Phase n Activities/Tasks: n Process Description: Used to define the internal workings of a process on the DFD. n Data Dictionary : Used to document the data definitions and formats.

Analysis Phase n Activities/Tasks: n Data Modeling: Designing the necessary databases and specifying how they may be accessed. n System Modeling: Using requirements to create actual plans for the new information system. n Project Management: The process of controlling the project to ensure schedules are met, estimates are updated, and costs are contained.

Detailed Analysis n Study the current system n Identify the users’ wants, needs, and requirements n Present alternative solutions

Detailed Analysis n 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 n Covert DFDs into structure charts (Hierarchical diagram of program modules) n User Interface design (Input/Output) –Forms n Data base design n Structured walkthroughs n Design Testing Procedures

Detailed Design of Software n Database design –Data store in DFD –Logical modeling (ER - diagrams) –Normalization (Data redundancy & integrity) n Data security n Program Design –Program Specification package –System Flowchart

Detailed Design of Software n CASE tools Computer-aided software engineering (CASE) n Graphics n Prototyping n Quality assurance n Code generators

Detailed Design n Quality review n Necessary to double-check assumptions and design n Structured walkthrough

IMPLEMENTATION PHASE – SDLC #4 Develop programs n Install and test the new system n Train and educate users n Convert to the new system

Develop programs n Program development life cycle (PDLC) – Analyze – Design the programs – Code – Test the programs – Maintain the programs

Implementation Phase n Install and test the new system n System test - verify that all programs work and work together n Integration test - verify that an application works with other application in the system n Acceptance test - performed by users with real data n Types of testing varies

IMPLEMENTATION PHASE – SDLC #4 n Train and educate users – Classroom-style lectures – One-on-one sessions – User manuals – CAI

IMPLEMENTATION PHASE – SDLC #4 n Convert to the new system n Direct n Parallel n Phased n Pilot conversion old New old Old New

SUPPORT PHASE – SDLC #5 n Conduct post-implementation system review n Identify errors n Identify enhancements n Monitor performance

n Questions and comments?