Systems Development Life Cycle

What is the System Development Cycle? What is an information system (IS)? Next Hardware, software, data, people, and procedures that work together to ...

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Systems Development Life Cycle •The Analysis Phase •Introduction to process modelling

What is the System Development Cycle? What is an information system (IS)?

Hardware, software, data, people, and procedures that work together to produce quality information

System—Set of components that interact to achieve common goal Businesses use many types of systems

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What is the System Development Cycle? What are the phases of the system development cycle? Phase 2. Analysis 

Phase 1. Planning  

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Review project requests Prioritize project requests Allocate resources Identify project development team

Conduct preliminary investigation Perform detailed analysis activities: Study current system Determine user requirements Recommend solution

Phase 5. Support 

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Conduct post-implementation system review Identify errors and enhancements Monitor system performance

Phase 3. Design 



Acquire hardware and software, if necessary Develop details of system

Phase 4. Implementation    

Develop programs, if necessary Install and test new system Train users Convert to new system Next

What is the System Development Cycle? What are guidelines for system development?

Arrange tasks into phases (groups of activities) Involve users (anyone for whom system is being built)

Develop clearly defined standards (procedures company expects employees to follow) Next

What is the System Development Cycle? Who participates in the system development life cycle?

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What is the System Development Cycle? What is a systems analyst? Responsible for designing and developing information system Liaison between users and IT professionals

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What is the System Development Cycle? What is the project team? Formed to work on project from beginning to end

Consists of users, systems analyst, and other IT professionals Project leader—one member of the team who manages and controls project budget and schedule

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What is the System Development Cycle? What is project management?  

Process of planning, scheduling, and controlling activities during system development cycle Project leader identifies elements for project

Goal, objectives, and expectations, collectively called scope

Required activities

Time estimates for each activity

Cost estimates for each activity

Order of activities

Activities that can take place at same time

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What is the System Development Cycle? What is a Gantt chart? 

Popular tool used to plan and schedule time relationships among project activities

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What is the System Development Cycle? What is project management software? 

Program (such as Microsoft Office Project 2003) used by project leaders to plan, schedule, and control projects

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What is the System Development Cycle? What is feasibility? Operational feasibility

Measure of how suitable system development will be to the company

Four feasibility tests: Schedule feasibility

Economic feasibility (also called cost/benefit feasibility)

Technical feasibility

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What is the System Development Cycle? What is documentation? Collection and summarization of data and information Includes reports, diagrams, programs, and other deliverables Project notebook contains all documentation for single project

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What is the System Development Cycle? What are six data and information gathering techniques?     



Review documentation Observe Questionnaire Interview Joint-application design (JAD) session Research Next

What Initiates the System Development Cycle? What are some reasons to create or modify an information system?

To correct problem in existing system

To improve existing system

Outside group may mandate change

Competition can lead to change

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What Initiates the System Development Cycle? What is a request for system services? 

Formal request for new or modified information system 

Also called project request

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Planning Phase What is the planning phase? Begins when steering committee receives project request Steering committee— decision-making body for the company

Function of committee: Review and approve project requests

Prioritize project requests

Allocate resources

Form project development team for each approved project Next

Analysis Phase What is the analysis phase?

Conduct preliminary investigation, also called feasibility study

Perform detailed analysis

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Analysis Phase What is the preliminary investigation? Determine exact nature of problem or improvement and whether it is worth pursuing

 

Findings are presented in feasibility report, also known as a feasibility study

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Analysis Phase What is detailed analysis? 1. Study how current system works 2. Determine user’s wants, needs, and requirements

3. Recommend solution

Sometimes called logical design Next

Analysis Phase What is process modeling? Technique that describes processes that transform inputs into outputs Also called structured analysis and design

Entity-relationship diagrams

Three tools used for process modeling

Data flow diagrams Project dictionary

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Analysis Phase What is an entity-relationship diagram (ERD)? 

Tool that graphically shows connections between entities in system

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Analysis Phase What is a data flow diagram (DFD)? 

Tool that graphically shows flow of data in system

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Analysis Phase What is a project dictionary? Contains all the documentation and deliverables of project

Helps keep track of huge amount of details in system

Variety of techniques to enter items in project dictionary Structured English Decision tables Decision trees Data dictionary Next

Analysis Phase What is Structured English? 

Used to explain details of process in project dictionary

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Analysis Phase What is a decision table? 

Lists variety of conditions and actions that correspond to each condition

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Analysis Phase What is a decision tree? 

Shows conditions and actions graphically

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Analysis Phase What is a data dictionary? 

Stores name, description, and other details about each data item

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Analysis Phase What is object modeling? Combines data with the processes that act on data into single unit called an object

Object—an item that can contain both data and procedures that read or manipulate the data

Sometimes called object-oriented (OO) analysis and design Uses Unified Modeling Language (UML)—graphical tool for documenting system Next

Analysis Phase What is a use case diagram? 

Graphically shows how actors interact with information system  

Actor—user or other entity Use case— function that actor can perform

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Analysis Phase What is a class diagram? 

Graphically shows classes and subclasses in system 

Class is group of objects— Can have lower levels called subclasses

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Analysis Phase What is the system proposal?

Assesses feasibility of each alternative solution

Recommends the most feasible solution for the project

Presented to steering committee, which decides how system will be developed

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Analysis Phase What are possible software solutions?

Horizontal market software—meets needs of many companies

Buy packaged software—prewritten software available for purchase Write own custom software—software developed at user’s request

Vertical market software—designed for particular industry

Outsource—have outside source develop software Next