A level-0 diagram represents the primary individual processes in the system at the highest possible level.
The information system is depicted as a DFD and the highest-level view of this system is called a context diagram.
There are two different standard sets of DFD symbols and each set consists of three symbols that represent the same things.
Sources/sinks are sometimes referred to as external entities because they are outside the system.
To avoid having data flow lines cross each other, you may repeat data stores or sources/sinks on a DFD. Use an additional symbol, like a double line on the middle vertical line of a data store symbol or a diagonal line in a corner of a sink/source square, to indicate a repeated symbol.
A data flow diagram (DFD) is a picture of the movement of data between external entities and the processes and data stores within or outside a system .
A level-0 diagram represents the primary individual processes in the system at the highest possible level.
The information system is depicted as a DFD and the highest-level view of this system is called a context diagram.
There are two different standard sets of DFD symbols and each set consists of three symbols that represent the same things.
Sources/sinks are sometimes referred to as external entities because they are outside the system.
To avoid having data flow lines cross each other, you may repeat data stores or sources/sinks on a DFD. Use an additional symbol, like a double line on the middle vertical line of a data store symbol or a diagonal line in a corner of a sink/source square, to indicate a repeated symbol.
A data flow diagram (DFD) is a picture of the movement of data between external entities and the processes and data stores within or outside a system .