Introduction SDLC relates to developments of projects in the information system. It ensures that the project meets all processes, functional, and user requirements (Roebuck 2). SDLC offers standardized and planned processes for all phases of the system development. SDLC stages start from feasibility study to other aspects of planning, design, development, integration, and maintenance of completed projects. There are many SDLC models, which provide guidance for project development processes. These include the waterfall model, rapid application development, joint application development, and fountain model among others. In some cases, developers of SDLC models have combined some of the models in order to produce hybrid models (Post, Anderson 89). It is necessary to note that various models have effective results in different applications. However, the most important factor that influences the project outcome is the planning and implementation process (Blanchard and Fabrycky 31). Generally, the SDLC model has six steps. The first step involves evaluation of the existing system. This is useful for identification of defects in the system. It may involve interviewing users and support teams. The second step involves identification of system requirements. This stage seeks to address various defects in the system with specific suggestions for enhancing the system. The third step is the design step. The developer must formulate plans for various aspects like operating systems, security features, hardware, physical development, and programming among others. The fourth step accounts for the system development. Developers must install all required components. At the same time, users must also get training. The system must undergo testing, and developers must make any necessary adjustments at this point. The fifth step involves the deployment of the system into use (testing). The new system can replace the old system or the developer can introduce the new system in phases. The final step involves evaluation of the new system during operation. Maintenance is also necessary at this stage. The system also requires constant updates based on new developments. Figure 1: System Development Life Cycle Data Flow Diagram (DFD) The DFD shows how systems process data in relation to inputs and outputs. The DFD is a graphical tool that highlights flow of data and stores data in its system. It shows how data undergo changes in a system. The DFD also has various symbols such as process flows, process symbols, data store and data flow symbols. The process symbol has entities to show the process number, locality, and process name (Shelly and Rosenblatt 332). DFD highlights all stages that information must originate from, go to, and where the system shall store such information. However, DFD does not show timing process. In addition, it does not indicate whether the flow of information is parallel or sequential as most graphical representations show. We have two categories of data flow diagrams, which are logical and physical. A logical DFD looks at how business and its processes run. It captures data needed and produced for each business process. Conversely, physical DFD focuses on implementation processe