Data Flow Diagram

Data Flow Diagram (DFD) is the part of the Structured Systems Analysis and Design Methodology (SSADM), which is intended for information systems projection and analysis. Data Flow Diagrams allow graphically represent the data flows in information system and analyze the data processing during the structural projection. This type of diagrams lets visually show a work of information system and results of this work, it is often used in connection with human processes and can be displayed as Workflow diagram. Data Flow Diagram visualizes processes and functions, external entities, data depositories, and data flows connecting these elements and indicating direction and data character. Each of these elements used for DFD has its own graphical notation. There are two notations to draw DFDs - Yourdon & Coad and Gane & Sarson. ConceptDraw DIAGRAM extended with Data Flow Diagrams (DFD) solution from Software Developmant area is ideal for designing professional looking DFDs, which can be then easily exported in various formats.

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.

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.

Data Flow Diagram Symbols. DFD Library

Data Flow Diagrams graphically represent the information transfers and process steps of a system. They visually depict how data are processed by a system in terms of inputs and outputs, how occurs the input in a system, how the data flow through an information system and where they are stored, and how occurs output from the system. DFDs give the overview of the system and models the processes aspects, they are maintained with other methods of structured systems analysis. The main goal of DFDs is achievement of understanding between developers and users. For their construction are used two notations - Gane-Sarson and Yourdon, each of them uses its own set of symbols. Data Flow Diagrams solution from Software Development area extends the ConceptDraw DIAGRAM software with templates, samples, and predesigned libraries of data flow diagram symbols for both notations, allowing you easy design the process-oriented and data-oriented models, draw the Data Flow Diagrams, Data Flowcharts, Data Process Diagrams, Information Flow Diagrams, Structured Analysis Diagrams, etc.

ConceptDraw DIAGRAM DFD Software

Our DFD software ConceptDraw DIAGRAM allows you to quickly create DFD with data storages, external entities, functional transforms, data flows, as well as control transforms and signals. DFD program ConceptDraw DIAGRAM has hundreds of templates, and a wide range of libraries with all nesassary ready-made drag-and-drop.

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.

Gane Sarson Diagram

The Gane-Sarson methodology uses the graphical techniques for building the logical models for the systems. It is helpful for analysts and designers to make common and clear picture of the system, to depict all its processes and how they transform the data. The Gane-Sarson methodology lets represent all this information in a way understandable for the users and other interested people, and gives the possibility to see instantly how the system's parts serve together to meet their needs. This methodology supposes the building of a system top-down. First you need create an overall system data flow, then determine the details of the data structures, the process logic and design the modular structures. ConceptDraw DIAGRAM diagramming and vector drawing software offers the Data Flow Diagrams solution with Gane-Sarson Notation library rich for the specific symbols of the Gane-Sarson notation. All they are vector and fully ready-to-use for drawing the Data Flow Diagrams, which will be then successfully used in presentations, websites, and various business documents.

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.

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.