The Systems Development Life Cycle: Overview
An information system includes a computer program, application, or combination of hardware and software that is developed to solve a specific problem. The process of creating an information system is referred to as the systems development life cycle (SDLC).
The SDLC has six phases:
- Project Planning: During the project planning phase the goals and objectives of the new system are clearly defined. A feasibility study is conducted to determine whether a new system is a feasible solution.
- Analysis: The role of the analysis phase is to identify detailed requirements for the system. What business needs will the information system fill? What outputs will it need to produce? Who will use it? How many users will need to use it at the same time? What other systems will it share data with?
- Generation and Evaluation of Alternatives: During this phase, alternative ways to address the requirements are researched. All solutions are compared according to technical aspects, organizational aspects, and the economics of the project.
- Design: Once a feasible solution has been selected, the design phase determines how the system will work. During the design phase, each portion of the new system is designed in detail, including the user interface, data structure, and the program design. The design phase often ends with a prototype — a working model of the system.
- Implementation: The next phase is to actually create the components of the system. Testing should be an integral part of this phase, ensuring that each component works as it should and that the design plan is being followed. When development is complete, it's time to put the system in place. This can mean installing the software on end-users' computers or uploading a Web site to a Web server.
- Maintenance and Operation: The work doesn't end with implementation. Ideally, the maintenance phase lasts until the system is no longer in use. The system must be monitored to ensure that it continues to work properly. Errors (or "bugs") may be found that need to be fixed, or new needs may arise which require modifications to the system. If the new needs cannot be met by the original system, the cycle starts over to design a significant modification to the system or to implement a new system.
