Objectives:-
*Define system development and list the system development phases.
*Identify the guidelines for system development.
*Discuss the importance of project management, feasibility assessment, documentation, and data and information gathering techniques.
*Explain the activities performed in the planning phase.
*Discuss the purpose of the activities performed in the analysis phase.
*Describe the various tools used in process modeling.
*Describe the various tools used in object modeling.
*Explain the activities performed in the design phase.
*Recognize the develop programs activity is part of system development.
*Discuss the activities performed in the implementation phase.
*Discuss the purpose of the activities performed in the operation, support, and security phase.
What is System Development:-
>System development is a set of activities used to build an information system.
>A system is a set of components that interact to achieve a common goal.
>An information system (IS) is a collection of hardware, software, data, people, and procedures that work together to produce quality information.
>System development activities are grouped into phases, collectively called the system development life cycle (SDLC).
>Project management is the process of planning, scheduling, and then controlling the activities during system development
>To plan and schedule a project efficiently, the project leader identifies:-
*Project scope.
*Required activities.
*Time estimates for each activity.
*Cost estimates for each activity.
*Order of activities.
*Activities that can take place at the same time.
>Feasibility is a measure of how suitable the development of a system will be to the organization.
>During system development, members of the project team gather data and information using several techniques:-
*Review documentation.
*Observe.
*Survey.
*Interview.
*JAD Sessions.
*Research.
Planning Phase:-
>The planning phase for a project begins when the steering committee receives a project request.
>Four major activities are performed:-
*Review and approve the project requests.
*Prioritize the project requests.
*Allocate resources.
*Form a project development team.
Analysis Phase:-
>The analysis phase consists of two major activities:-
Conduct a preliminary investigation
*Determines and defines the exact nature of the problem or improvement.
*Interview the user who submitted the request.
Perform detailed analysis
*Study how the current system works.
*Determine the users’ wants, needs, and requirements.
*Recommend a solution.
>Process modeling (structured analysis and design) is an analysis and design technique that describes processes that transform inputs into outputs.
>An entity-relationship diagram (ERD) is a tool that graphically shows the connections among entities in a system.
>Entities are objects in the system that have data.
>A data flow diagram (DFD) is a tool that graphically shows the flow of data in a system
*Data flows.
*Processes.
*Data stores.
*Sources.
>The project dictionary contains all the documentation and deliverables of a project.
>Structured English is a style of writing that describes the steps in a process.
>A decision table is a table that lists a variety of conditions and the actions that correspond to each condition.
>A decision tree also shows conditions and actions, but it shows them graphically.
>The data dictionary stores the data item’s name, description, and other details about each data item.
>UML (Unified Modeling Language) has been adopted as a standard notation for object modeling and development.
*UML includes 13 different diagrams
*Two diagrams include:-
-Use case diagram.
*graphically shows how actors (users) interact with the information system.
-Class diagram.
*graphically shows classes and subclasses in a system.
>The system proposal assesses the feasibility of each alternative solution.
>The steering committee discusses the system proposal and decides which alternative to pursue.
Design Phase :-
>The design phase consists of two major activities.
*Acquire hardware and software.
*Develop all of the details of the new or modified information system.
Implementation Phase :-
>The purpose of the implementation phase is to construct the new or modified system and then deliver it.
>Various tests should be performed on the new system.
Unit test
*verifies that each individual program or object works by itself
Systems test
*verifies that all programs in an application work together properly
Integration test
*verifies that an application works with other applications
Acceptance test
*checks the new system to ensure that it works with actual data.
>Training involves showing users exactly how they will use the new hardware and software in the system:-
*One-on-one sessions.
*Classroom-style lectures.
*Web-based training.
>One or more of four conversion strategies can be used to change from the old system to the new system.
Operation,Support and Security Phases:-
>The purpose of the operation, support, and security phase is to provide ongoing assistance for an information system and its users after the system is implemented.
Perform maintenance activities -> Monitor system performance ->
Assess system security.
>A computer security plan should do the following:-
*Identify all information assets of an organization.
*Identify all security risks that may cause an information asset loss.
*For each risk, identify the safeguards that exist to detect, prevent, and recover from a loss.
Summary :-
*System development phases.
*Guidelines for system development.
*Activities that occur during system development.
*Activities performed during each system development phase.
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