Enterprise AI Glossary · Reviewed June 2026

Vector Database

A database optimized for similarity search over embedding vectors.

What is Vector Database?

A vector database is the storage layer behind RAG. In a private deployment, it sits next to the documents it indexes — not in a separate vendor tenant — so retrieval, permissions, and audit live in one boundary. See Vector Database and Private RAG.

Why it matters for on-premise & regulated AI

Your vector database is a compressed copy of your most sensitive documents — embeddings can be partially inverted back to text. Hosting it as a managed cloud service means your knowledge base lives outside your boundary regardless of where the LLM runs. Self-hosted vector stores (pgvector, Qdrant, Milvus) keep the index under the same controls as the source documents, which is why on-prem RAG architectures default to them.

Go deeper

Read the full guide: Vector Database — in-depth article →

Related terms

Putting Vector Database to work?

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