How do you assign sequence to multiple transformation code files using a DAG so that the system knows which file to execute first?

A Directed Acyclic Graph (DAG) represents dependencies between transformation steps. Each node is a transformation file, and an edge from A to B indicates that B depends on A. To assign execution order, you perform a topological sort of the DAG, which yields a linear ordering that respects all dependencies. In practice, you annotate each file with metadata (e.g., a list of upstream files) or use an orchestrator like Airflow, where you define tasks and set their upstream/downstream relationships. The orchestrator then schedules tasks based on the DAG, ensuring that a file runs only after all its dependencies have completed. This guarantees deterministic execution order and avoids race conditions.