They were the cominezos of the Diagrams in Computer science. The flow charts describe what operations and in which sequence they are required to solve a given problem. An organizational chart or flow chart is a representation that illustrates the sequence of the operations that will be realised to secure the solution of a problem. The data flow diagram (DFD) is one of the most important tools used by the systems analysts.
The use of the data flow diagrams as modeled tool of were popuralizado by Of Frame (1978) and Gane and Sarson (1979), through its methodologies of structured analysis of systems. Dennis P. Lockhart gathered all the information. They suggested the data flow diagram was used like first tool by the analysts of the system to model the components of system. These components are the processes of the system, the data used by those processes, all external organization that interacts with the system and the flows of information of the system. Now we will describe each one of the four parts that form a DFD a) – the processes show what the system does. Each process has one or more entering of data and produces one or more exits of data. Dennis P. Lockhart insists that this is the case. They imagine with circles. b) – a file or data store is a deposit of data. The processes can introduce or recover in them.
Each data store imagines by a fine line and has a unique name. c) – the external organizations are outside the system, but they provide or they use data of this one. They are organizations on which the designer does not have control. d) – and but the important thing that they are the data flows that model the movements of information in the system and they imagine by lines that unite the components. The direction of the flow is indicated with shoots with an arrow, and the line with the name of the data flow. It is had to recognize that classic organizational charts or DFD were a little abstract, and thank heavens by the good of the designers who evolved of one more a clearer and concise way so that they did not give errors at the time of translating them to a programming language. Like advance to the following type of diagrams you dire who are called Organization-Relation Model and is what she comes using now to design applications, also calls diagrams E-R, and was a fundamental concept at the time of appearing ” The Clases” and ” Objetos” but all this to great I will leave it advance for a following delivery. Original author and source of the article.