The problem RAG exists to solve

A large language model only knows what was in its training data, up to a cutoff date — it has never seen your internal wiki, your product catalog, or last week's support tickets. Fine-tuning a model on that data is possible, but it's expensive to keep current and it doesn't let the model cite where an answer came from. Retrieval-Augmented Generation (RAG) takes a different approach: instead of teaching the model your data, it hands the model the relevant pieces of your data at the moment it answers.

How it works, step by step

Question Embed Vector Search LLM → + retrieved documents

1. Embed: your documents (or table rows, or support tickets) are converted into vector embeddings — numerical representations that place semantically similar content close together in vector space.

2. Store: those embeddings are saved in a vector database (or a vector index inside your existing warehouse) alongside a reference back to the original document.

3. Retrieve: when a question comes in, it's embedded the same way, and the vector store returns the handful of documents most semantically similar to it.

4. Augment and generate: those retrieved documents are inserted into the model's prompt alongside the question, so the model answers using your actual content instead of relying on what it memorized during training.

A minimal example


query_embedding = embed(question)
top_docs = vector_store.similarity_search(query_embedding, k=4)

prompt = f'''
Answer using only the context below. If the answer isn't in the
context, say you don't know.

Context:
{format_docs(top_docs)}

Question: {question}
'''
response = llm.generate(prompt)
The instruction to only use the provided context is doing real work here — it's what keeps the model from filling gaps with plausible-sounding but ungrounded answers.

Where RAG fits into a real data platform

Governed data Warehouse (BI) Vector store (RAG) same access rules apply
RAG isn't a replacement for your warehouse — it's a new consumer of the same governed data. The documents that get embedded still need the same access controls and classification discussed in our article on data governance for AI: if a document is restricted in the warehouse, it should never end up retrievable by a model serving a broader audience. Treating the vector store as just another governed data product, not a side project, is what keeps a RAG system trustworthy as it scales past the first demo.

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