Data flow connects inputs to the operations and components that consume or transform them. Following a flow can reveal validation steps, state changes, persistence, and the source of values shown to a user.
For AI-assisted development, understanding an existing data flow helps constrain a change and identify relevant failure cases. A replacement interface may look correct while handling missing values, updates, or saved records differently from the original system.
ELI5
Data flow is the journey information takes through an application. Following that journey helps explain where a value came from and what happened to it.
For example, a delivery address moves from a form through validation into storage and then into an order confirmation. A mistake at any step can affect the address the customer sees.
Why trace data flow before changing software?
It reveals dependencies and behavior that might be affected even when the edited code is small.
Is data flow limited to movement between files?
No. It can occur within a function, between application components, across services, or between a program and its storage.
