THE SYSTEMS DEVELOPMENT LIFE CYCLE (SDLC)
SDLC Waterfall Methodology
SDLC-is a methodology for the design and implementation of an information system in an organization.
ü A methodology is a formal approach to solving a problem based on a structured sequence of procedures.
ü SDLC consists of 6 phases.
It is the most important phase and it begins with an examination of the event or plan that initiates the process.
During this phase, the objectives, constraints, and scope of the project are specified.
At the conclusion of this phase, a feasibility analysis is performed, which assesses the economic, technical and behavioral feasibilities of the process and ensures that implementation is worth the organization’s time and effort.
It begins with the information gained during the investigation phase.
It consists of assessments (quality) of the organization, the status of current systems, and the capability to support the proposed systems.
Analysts begin by determining what the new system is expected to do, and how it will interact with existing systems.
This phase ends with the documentation of the findings and an update of the feasibility analysis.
In this phase, the information gained from the analysis phase is used to begin creating a systems solution for a business problem.
Based on the business need, applications are selected that are capable of providing needed services.
Based on the applications needed, data support and structures capable of providing the needed inputs are then chosen.
In this phase, analysts generate a number of alternative solutions, each with corresponding strengths and weaknesses, and costs and benefits.
At the end of this phase, another feasibility analysis is performed.
In this phase, specific technologies are selected to support the solutions developed in the logical design.
The selected components are evaluated based on a make-or-buy decision.
Final designs integrate various components and technologies.
In this phase, any needed software is created.
Components are ordered, received and tested.
Afterwards, users are trained and supporting documentation created.
Once all the components are tested individually, they are installed and tested as a system.
Again a feasibility analysis is prepared, and the sponsors are then presented with the system for a performance review and acceptance test.
Maintenance and change
It is the longest and most expensive phase of the process.
It consists of the tasks necessary to support and modify the system for the remainder of its useful life cycle.
Periodically, the system is tested for compliance, with business needs.
Upgrades, updates, and patches are managed.
As the needs of the organization change, the systems that support the organization must also change.
When a current system can no longer support the organization, the project is terminated and a new project is implemented.