Components of Data Flow Diagrams (DFD)
The Data Flow Diagram has 4 components:
- Process: Input to output transformation in a system takes place because of process function. The symbols of a process are rectangular with rounded corners, oval, rectangle or a circle. The process is named a short sentence, in one word or a phrase to express its essence
- Data Flow: Data flow describes the information transferring between different parts of the systems. The arrow symbol is the symbol of data flow. A relatable name should be given to the flow to determine the information which is being moved. Data flow also represents material along with information that is being moved. Material shifts are modeled in systems that are not merely informative. A given flow should only transfer a single type of information. The direction of flow is represented by the arrow which can also be bi-directional.
- Warehouse (Data Store) : The data is stored in the warehouse for later use. Two horizontal lines represent the symbol of the store. The warehouse is simply not restricted to being a data file rather it can be anything like a folder with documents, an optical disc, a filing cabinet. The data warehouse can be viewed independent of its implementation. When the data flow from the warehouse it is considered as data reading and when data flows to the warehouse it is called data entry or data updating.
- Terminator (External Entity): The Terminator is an external entity that stands outside of the system and communicates with the system. It can be, for example, organizations like banks, groups of people like customers or different departments of the same organization, which is not a part of the model system and is an external entity. Modeled systems also communicate with terminator.
Basic Structure of Data Flow Diagram (DFD)
What symbols and notations are used to represent Components of DFD?
In Data-Flow Diagrams (DFDs), symbols and notations vary depending on the methodology being used. Here’s a summary of symbols and notations commonly associated with each methodology:
The different methodologies or approaches used for creating Data-Flow Diagrams (DFDs) are:
- Gane and Sarson
- Yourdon and De Marco
- SSADM
- UML
Each methodology provides its own set of guidelines, symbols, and notations for representing system components and their interactions.
Data Flow Diagram Methods and Symbol
What is DFD(Data Flow Diagram)?
Data Flow Diagram (DFD) represents the flow of data within information systems. Data Flow Diagrams (DFD) provide a graphical representation of the data flow of a system that can be understood by both technical and non-technical users. The models enable software engineers, customers, and users to work together effectively during the analysis and specification of requirements.
Table of Content
- What is Data Flow Diagram (DFD)?
- Characteristics of Data Flow Diagram (DFD)
- Physical and Logical data flow diagrams (DFDs)
- Components of Data Flow Diagrams (DFD)
- Levels of Data Flow Diagram (DFD)
- Rules for Data Flow Diagram (DFD)
- Advantages of Data Flow Diagram (DFD)
- Disadvantages of Data Flow Diagram (DFD)
- How to Draw Data Flow Diagram?
- Conclusion
- Frequently Asked Questions (FAQs) related to Data Flow Diagram (DFD)