1 California State University, Fullerton Chapter 13 Developing and Managing Information Systems.
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1 California State University, Fullerton Chapter 13 Developing and Managing Information Systems
2 California State University, Fullerton People in Information Systems Development Systems analysts follow a step-by-step process to develop information systems. Information systems are usually developed by a group of people who form a project team.
3 California State University, Fullerton The Systems Development Process The system development process, which also called the System Development Life Cycle (SDLC) is divided into five main phases: 1.System planning 2.System analysis 3.System design 4.System implementation 5.System maintenance
4 California State University, Fullerton System Planning System planning is the phase in which the systems analyst decides whether a new information system should be developed. The systems analyst conducts a feasibility analysis. Technological feasibility Organizational feasibility A cost/benefit analysis (economic feasibility) is prepared.
5 California State University, Fullerton System Analysis During system analysis, the analyst studies the existing and determines what the new system must do. Studies the existing system Defines user requirements Develop a conceptual or general design Evaluate hardware and software alternatives Packaged software Custom software
6 California State University, Fullerton System Design During system design, the analyst specifies the detail of how the new system will function. Describing design details including layouts of screens, forms and reports; specifications for all hardware; descriptions of all programs.
7 California State University, Fullerton System Implementation During system implementation, the systems analyst acquires (purchase/build) the components of the system – such as: Hardware Acquisition Software acquisition or programming Testing Site preparation and installation Training System conversion
8 California State University, Fullerton System Implementation (cont’d.) Four methods of converting to the new system: Plunge – old system is turned off, new one is turned on. Phased – new system is divided into parts with one part phased in at a time. Pilot – new system is installed in a part of the organization. Parallel – old and new systems are used simultaneously for a period of time.
9 California State University, Fullerton System Maintenance System maintenance involves modifying the system during its life to meet new requirements. Maintenance is required for three reasons: 1.Errors found that were not detected in testing 2.A new function is to be added to the system 3.The requirements have changed
10 California State University, Fullerton System Development Tools Data Flow Diagrams (DFD) Entity-Relationship Diagram (ERD) Computer Aided Software Engineering (CASE) tools
11 California State University, Fullerton Data Flow Diagrams A tool many analysts use to show the flow of data in an information system. The diagram uses symbols with different shapes to indicate how data flows in the system. They are: Process – a rounded corner rectangle External entity – a rectangle Data store – an open rectangle Data flow – an arrow
12 California State University, Fullerton Entity-Relationship Diagram An entity is something about which data is stored in a database. A relationship is an association between entities. An entity-relationship diagram shows the entities and relationships between entities in a database.
13 California State University, Fullerton CASE Tools CASE – Computer Aided Software Engineering – tools are computer based tools such as those for system development.
14 California State University, Fullerton Prototyping Prototyping involves the systems analyst obtaining informal and incomplete requirements for the system and developing a prototype, which is a simplified version of the system that acts like the real system but may not perform all the required functions of the system.
15 California State University, Fullerton Individual Information System Development The five steps of the SDLC serve as a general guide. Individual information system planning starts when the user recognizes a problem or a need. Must consider whether personal technical skills are adequate.
16 California State University, Fullerton Electronic Commerce System Development While similar to the steps in the SDLC, there are notable differences: In e-commerce systems, the main user is the customer.
17 California State University, Fullerton Electronic Commerce System Development (cont’d.) Design of an e-commerce system involves two main parts: Front end – is what the customer sees when they use the system. Back end – provides the capabilities necessary for completing the customer’s order including inventory control and product distribution.
18 California State University, Fullerton Electronic Commerce System Development (cont’d.) Publishing the system is the process of setting up the system on a server and making it available through the Internet.
19 California State University, Fullerton Business Process Reengineering Business Process Reengineering (BPR) involves completely redesigning the business processes, which are groups of activities or tasks that accomplish things for a business. BPR is not gradual improvement, but rather radical redesign of business processes.