Two terms that one often hears in relation to information systems development are methodologies and tools. A methodology is a recommended way of doing something, and a tool is a device for accomplishing a task. Relating these terms to the building of a house, the arhchitect’s blueprint is a methodology (the architect’s recommended way of building the house), and the tools are what the construction workers use to actually build the house (nail guns, circular saws, and electric drills).
An information system methodology is a recommended way to develop an information system. A System Development Life Cycle (SDLC) is a series of stages within the methodology that are followed in the process of developing and revising an information system. A stage is a segment of an SDLC that consists of certain types of activity. Stages are usually completed in a certain sequence using software development tools.
Developers use system design tools for data, process, and object modeling. Data modeling tools include entity-relationship diagrams (ERDs) and data dictionaries. Process modeling tools include data fl ow diagrams (DFDs) and use case diagrams. Object modeling tools include class and sequence diagrams. Business processing uses workfl ow diagrams (WFDs).