How would you design a RAG system that handles both documents and structured data?

Route queries based on intent using a classifier or language model, sending structured queries to a SQL database or search index and unstructured queries to vector retrieval. For hybrid queries that need both, run them in parallel and combine results in the prompt, clearly labeling which facts come from which source. Tools like text-to-SQL for database queries and vector search for documents can share a single agent that decides which tools to invoke. Self-query retrievers handle structured filters over metadata within the vector store.