Garishma se
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A data flow diagram (DFD) is a graphical representation of the flow of data through a system. It uses symbols like rectangles, circles, and arrows to show data inputs, outputs, storage points, and the routes between each destination. A DFD shows what data will be input and output from the system and where data will be stored. It also shows external entities, processes, data stores, and data flows. There are three levels of a DFD - level 0 provides an overview, level 1 provides more detail, and level 2 provides further detail into parts of level 1. A DFD is used to create an overview of a system without detail and can also visualize data processing.
Garishma se
- 1. By : Garishma Bhatia
- 2. A data flow diagram also known as DFD. A DFD is a graphical representation of the "flow" of data through an information system. It uses defined symbols like rectangles, circles and arrows, to show data inputs, outputs, storage points and the routes between each destination.
- 3. A DFD shows what kind of information will be input to and output from the system. where the data will be stored
- 4. External entity: an outside system that sends or receives data. Process: any process that changes the data. Data store: files that hold information for later use. Data flow: the route that data takes between the external entities.
- 6. Each process should have at least one input and an output. Each data store should have at least one data flow in and one data flow out. Data stored in a system must go through a process. All processes in a DFD go to another process or a data store.
- 7. There are mainly three types of data flow diagram: - level 0 - level 1 - level 2
- 8. DFD Level 0 is also called a Context Diagram. It’s a basic overview of the whole system.
- 9. DFD Level 1 provides a more detailed of the Context Level Diagram.
- 10. DFD Level 2 then goes one step deeper into parts of Level 1. It may require more text to reach the necessary level of detail about the system’s functioning.
- 12. Progression to Levels 3, 4 and beyond is possible, but going beyond Level 3 is uncommon
- 13. A DFD is often used to create an overview of the system without going into detail, which can later be elaborated DFDs can also be used for the visualization of data processing.
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