Managing dynamically changing directed acyclic graphs (DAGs) with constraints in Postgres is essential for robustly tracking evolving relationships, such as those in fleet management where vehicles frequently attach and detach. At traconiq, the use of Neon serverless Postgres as an operational database layer allows for the enforcement of DAG integrity, handling time-variant relationships, and resolving conflicting data from multiple sources. The schema design uses temporal types and constraints to capture the time-varying structure, ensuring data integrity by preventing cycles and maintaining single incoming edges per node. Deferred constraint triggers ensure these rules are enforced post-transaction, while functions like add_edge() manage conflict resolution and interval updates. This setup facilitates querying and traversing the graph within Postgres, providing both historical and real-time insights. The combination of Postgres features and Neon's infrastructure supports scalable, consistent modeling of evolving relationships, with full code available open source for adaptation to similar use cases.