Data Flow Diagrams (DFD)

Data Flow Diagram (DFD)

A Data Flow Diagram (DFD) illustrates the flow of data through an information system, visualizes how the information is handled in terms of inputs and outputs, how the data enter to system and leave it. It is effective to use a Data Flow Diagram for creation the system's overview, to show the system's scope and boundaries. There are two different types of notations for DFDs: Yourdon-Coad and Gane-Sarson, which differ in visual representations for processes, data flow, data stores, external entities, etc. Thus, for example the processes are depicted as circles in Yourdon-Coad notation and as rounded squares in Gane-Sarson notation. Gane-Sarson notation is usually used for visualization information systems and Yourdon-Coad - for system analysis and design. The Data Flow Diagrams solution included to Software Development area of ConceptDraw Solution Park offers a lot of DFD templates, samples and examples, libraries of vector stencils for construction without efforts the DFDs according to both Gane-Sarson and Yourdon-Coad notations.

Data Flow Diagram Model

Data Flow Diagram (DFD) is a technique of graphical structural analysis, describing the sources external to the system, recipients of data, also logical functions, data flows and data stores that are accessed. The DFD's goal is to show how each process converts its inputs into the outputs and to identify relationships between these processes, at this make the system's description clear and understandable at every level of detail. Historically happened that for describing Data Flow Diagrams are used two notations - Yourdon and Gane-Sarson that differ each from other by graphical representation of symbols. The DFD model, like most other structural models is a hierarchical model. Each process can be subjected to decomposition on the structural components, the relationships between which in the same notation can be shown on a separate diagram. Typically, several DFD models are built when modeling the system. ConceptDraw DIAGRAM software enhanced with Data Flow Diagrams solution ideally suits for creation DFD models and professional drawing Data Flow Diagrams.

Data Flow Diagram Process

Data Flow Diagram (DFD) is a hierarchy of functional processes, connected by data flows. The purpose of this presentation is to show how each process converts its inputs into outputs and to identify relationships between these processes. DFD is convenient way of modeling and construction the information processes, it step-by-step illustrates the flow of information in a process. For construction a DFD traditionally are used two different notations, which appropriate to the methods of Yourdon-Coad and Gane-Sarson. These notations slightly different from each other by graphical representation of symbols for processes, data stores, data flow, external entities. When designing a DFD it is required to decompose the system into the components (sub-systems), for explaining a complex system you may need represent numerous levels. The Data Flow Diagrams solution from ConceptDraw Solution Park contains numerous predesigned DFD symbols for both notations, which help easy and effectively design professional-looking Data Flow Diagrams (DFDs) and DFD Process Diagrams.

Data Flow Diagram Examples

Data flow diagrams (DFDs) are effective to reveal relationships among the various components in a program or system. This type of diagrams is an important and useful technique for modeling an information system, its process aspects, for showing a system as a single high-level process. DFD lets illustrate the flow of data, how the input data are transformed to output results across the sequence of functional transformations. DFD consists of four major components: entities, processes, data stores, data flows. When you need to draw a Data Flow Diagram the ConceptDraw DIAGRAM diagramming and vector drawing software extended with Data Flow Diagrams solution will be helpful for you. Providing numerous collection of Data Flow Diagram examples, samples, templates and ready-to-use vector DFD symbols, Data Flow Diagrams solution ensures you with all needed tools for easy designing DFDs according to Gane-Sarson or Yourdon-Coad notation on your choice. Any from offered predesigned DFD examples can become a perfect base for your own diagram.

Design Data Flow. DFD Library

Data flow diagram or DFD is a type of diagrams used for graphical representation the "flow" of data through an information system, for effective modeling its process aspects and for visualization the data processing. They are one of the best tools for clearly making an overview of the system that will be developed, for depiction in details what kinds of information will be inputted to the system and outputted from it, where they will be stored, and other details. ConceptDraw DIAGRAM software with Data Flow Diagrams solution from Software Development area of ConceptDraw Solution Park is powerful in a field of designing the DFDs. Three libraries containing 49 vector DFD shapes and symbols are offered by Data Flow Diagrams (DFD) solution. Use them to design data flow diagrams, information flow diagrams, data flowcharts, data process diagrams, structured analysis diagrams, to create the data-oriented models or process-oriented models, and so on. Pay also attention for the included collection of DFD samples, examples and built-in templates at ConceptDraw STORE.

Example of DFD for Online Store (Data Flow Diagram)

Data Flow Diagram (DFD) is a methodology of graphical structural analysis and information systems design, which describes the sources external in respect to the system, recipients of data, logical functions, data flows and data stores that are accessed. DFDs allow to identify relationships between various system's components and are effectively used in business analysis and information systems analysis. They are useful for system’s high-level details modeling, to show how the input data are transformed to output results via the sequence of functional transformations. For description of DFD diagrams are uses two notations — Yourdon and Gane-Sarson, which differ in syntax. Online Store DFD example illustrates the Data Flow Diagram for online store, the interactions between Customers, Visitors, Sellers, depicts User databases and the flows of Website Information. ConceptDraw DIAGRAM enhanced with Data Flow Diagrams solution lets you to draw clear and simple example of DFD for Online Store using special libraries of predesigned DFD symbols.

DFD Library System

The Data Flow Diagram (DFD) is a graphical technique used for effective modeling and analyzing the information processes and systems. Having at the disposal the DFD library system and newest powerful tools of ConceptDraw DIAGRAM diagramming and vector drawing software supplied with Data Flow Diagrams (DFD) solution from the Software Development area of ConceptDraw Solution Park, you can design fast and easy the Data flow diagrams, Data flowcharts, Data flow models, Data flow process diagrams, Process-oriented models, Data-oriented models, Data process diagrams, Structured analysis diagrams, Information flow diagrams of any type and complexity. For designing the Data Flow Diagrams in ConceptDraw DIAGRAM software are used the simple DFD flowchart symbols from the offered DFD libraries - Data Flow Diagram (DFD) library, Yourdon and Coad Notation library, and Gane-Sarson Notation library. The DFD objects are need to be connected each other by the arrows to depict the data flow from one step to another, that you can do in seconds in ConceptDraw DIAGRAM , as well as set desired design of your diagram.

Structured Systems Analysis and Design Method. SSADM with ConceptDraw DIAGRAM

Structured Systems Analysis and Design Method (abbr. SSADM) is a method developed in Great Britain and accepted in 1993 as a national standard for information systems development and analysis. SSADM is based on Data Flow Diagrams and is characterized with presence of clear sequence of steps at projecting, analysis, and documenting of information system. It involves 6 main stages: analysis of existing system or estimation of practicability, requirements definition, determination of technical requirements and equipment cost, development of logical data model, projecting of logical requirements and specification them, physical projecting. Each of them is also divided into several steps defining the tasks that should be fulfilled at a given stage. The most important SSADM elements are flows modeling with help of DFD, data logic modeling with help of LDS (Logical Data Structure) and description of entities behavior. Applying of SSADM is easy with ConceptDraw DIAGRAM diagramming and vector drawing software and Data Flow Diagram solution.

DFD Library — Design elements

Data Flow Diagrams (DFD) solution from the Software Development area of ConceptDraw Solution Park provides plenty of predesigned templates, samples and DFD vector design elements proposed by three DFD libraries. These DFD library objects are designed to help you effectively model the data flows and functional requirements for the business processes or systems, to design the Process-oriented models or Data-oriented models, Data flowcharts and Data process diagrams, Structured analysis diagrams and Information flow diagrams. There are two different notations used to draw the Data Flow Diagrams (Yourdon & Coad and Gane & Sarson). These notations define the different visual representations for the processes, data stores, data flows, and external entities. ConceptDraw DIAGRAM software provides you with possibility of designing professional-looking Data Flow Diagrams, DFD Models, Data Flow Process Diagrams using any of these notations. Simply drag the predesigned DFD flowchart symbols from the appropriate library and connect by arrows depicting the data flow from one step to another.