1California State University, Fullerton

Chapter 13

Developing and Managing Information Systems

2California 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.

3California 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 planning2. System analysis3. System design4. System implementation5. System maintenance

4California 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.

5California 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

6California 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.

7California 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

8California 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.

9California 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

10California State University, Fullerton

System Development Tools Data Flow Diagrams (DFD) Entity-Relationship Diagram (ERD) Computer Aided Software

Engineering (CASE) tools

11California 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

12California 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.

13California State University, Fullerton

CASE Tools CASE – Computer Aided Software

Engineering – tools are computer based tools such as those for system development.

14California 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.

15California 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.

16California 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.

17California 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.

18California 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.

19California 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.