Data Flow Diagrams (DFDs) are a graphical representation of the flow of data within a system. They are used to visualize how data is processed, from its entry points to its exit points, and to identify the system's inputs, outputs, and transformations. They provide a visual representation of the system's structure and the relationships between data and processes. DFDs are useful for system analysis, process improvement, and identifying potential areas of error. They are also helpful in developing new systems or improving existing systems.

With our Data Flow diagrams, you can visualize what functions and objects interact with a given entity. We have two data flow diagrams in Understand that let you see how data flows into an object and how data flows out, and they are named Data Flow In and Data Flow Out, respectively.

In this simple example, we can see the Data Flow In graph for the global object Prefix from the zlib open source project.

It's clear from the Info Browser that there are only two places prefix has data flowing into it, once where it is defined and once where it is set

On the other hand, it is only used once, so the data flow out of it is quite simple at first

However, lunpipe has a lot more data flowing out of it, including a recursive use of prefix, so the dataflow out at two levels is quite a bit more complicated. To make it a little more clear you can switch to the clustered version of the graph which groups each entity in the corresponding files and architectures

You can right-click on any of the edges to view and jump to the references they represent. There is also a legend that shows that each colored line is a different reference kind and that the shapes indicate different entity kinds.