AI GLOSSARY
Vector Database
The technical foundation for semantic search and retrieval-augmented generation. Why traditional SQL databases reach their limits in AI applications—and how vector databases do things differently.
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Millions
vectors that a modern database handles
Vendor
on the market
Milliseconds
Typical query response time
Core components
of a vector database architecture
Why Vector Databases Are Essential for AI Projects
Without a vector database, there can be no productive RAG. Anyone building AI applications based on their own documents—from AI chatbots to knowledge assistants to copilots—needs a database that searches for semantic meaning, not just compares characters.
Semantic Search
Users find content that matches their search intent—even if no exact word matches.
Basis for RAG
Vector databases provide the relevant documents that serve as context for the LLM at runtime.
Scalable to millions of documents
Queries in the millisecond range, even when millions of documents are indexed.
Multimodal Support
Not just text: Images, audio, and drawings can also be saved and searched as vectors.
Fewer Hallucinations
Precise retrieval delivers the right sources—the AI doesn't have to guess.
Foundation for AI Agents
Agents access knowledge through the vector database. Without it, there is no context and no reliable action.
What is a vector database?
A vector database is a data storage system that stores content not as text or table rows, but as mathematical vectors (known as embeddings). These vectors represent the meaning of a document in a multidimensional space.
The key difference from a traditional SQL database is this: Instead of asking, “Give me all rows that contain the word ‘invoice,’” you ask a vector database, “Which documents are most similar in content to a given query?” It returns the semantically most similar results—even if none of the exact words match.
Vector databases are thus the backbone of Retrieval-Augmented Generation (RAG). They provide, at runtime, the relevant text snippets that a language model needs to generate fact-based responses.
Well-known examples include Azure AI Search, Pinecone, Weaviate, Milvus, Qdrant, and Chroma. For small and medium-sized businesses, the choice is less a matter of brand and more a matter of integration, operating model, and data protection.
A Comparison of Major Vector Databases
The market is diverse—the right database depends on your cloud strategy, your data protection requirements, and integration needs. Here’s an overview of common options:
Azure AI Search
Pinecone
Weaviate
Milvus
Qdrant
Chroma
pgvector
Elasticsearch
Best Practices for Vector Databases
In production vector setups, these basic principles quickly pay off:
- Test your chunking strategy: The right chunk size determines the quality of the results—paragraphs, sentences, or semantically divided.
- Store metadata: Source, author, date, and category enable precise filtering and access controls.
- Use hybrid search: Combine semantic vector search with traditional text search.
- Incorporate a re-ranker: A second model sorts the top results by relevance to the prompt.
- Respect permissions: Only include chunks in the search results that the user is authorized to view.
- Schedule updates: Changes to source documents must be reflected in the vector index in a timely manner.
Option 1
Managed (e.g., Pinecone, Azure AI Search)
Ready-to-use cloud service with an SLA. Quick to get started, predictable costs, low operational overhead.
Standard setup
Option 2
Self-Hosted Open Source
Weaviate, Milvus, Qdrant, or Chroma on your own infrastructure. Full control over your data, but with higher operational overhead.
Data-Critical
Option 3
SQL + Vector Extension
PostgreSQL with pgvector. Ideal if you’re already using Postgres and want to avoid a separate system.
Pragmatic
Common Mistakes in Vector Databases
Even with the best database, projects can fail due to avoidable errors:
- Incorrect chunk size: Too small → no context. Too large → vague results.
- No metadata: Without authorization filters, users see content they shouldn’t be able to see.
- Outdated embeddings: If the embedding model changes, the index must be rebuilt.
- No quality measurement: Without evaluations, poor retrieval goes undetected.
- Neglected data protection: Vectors can reveal information about the original content—clearly regulate storage location and access.
Vector DB vs. SQL vs. Search Engine
Three database paradigms with very different strengths:
- SQL database: Structured data in rows and columns. Perfect for transactions and master data—no semantics.
- Search engine: Full-text search with ranking. Finds words but does not understand meaning.
- Vector database: Semantic search based on meaning. The foundation for AI applications using your own documents.
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Frequently Asked Questions About the Vector Database
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Why do you need a vector database in the first place?
For semantic search within your own documents. Traditional databases compare characters; vector databases compare meaning. This is the foundation for RAG, AI chatbots, and Copilot applications.
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Can't I just keep using my SQL database?
For structured queries, yes. For semantic search in continuous text, you would need at least a vector extension such as pgvector in PostgreSQL. For very large data sets, a dedicated vector database is usually more cost-effective.
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Which vector database does prodot recommend for small and medium-sized businesses?
For Microsoft-focused companies, it's usually Azure AI Search. Those already using Postgres often start with pgvector. For open-source setups, we recommend Weaviate and Qdrant. The decision is made during the AI workshop.
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How much does a vector database cost?
The storage itself is manageable. The main cost drivers are usually the embedding calculation and the ingest pipeline. For a pilot project with a few thousand documents, costs typically stay under €500 per month.
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How are the vector database and RAG related?
RAG is the architecture; the vector database is the underlying data layer. Without a vector database, there can be no productive RAG—it provides the relevant chunks for the prompt.
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Is this use compliant with the GDPR?
Yes, if it's set up correctly. Key points: storage location, permissions in search results, handling of personal data, and data processing on behalf of third-party providers.
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How often does the vector index need to be updated?
Whenever source documents change. In production environments, incremental updates run automatically—daily, hourly, or on an event-driven basis.
Set Up a Vector Database for Your AI Application
During a free initial consultation, we’ll analyze your data sources, requirements, and cloud strategy. Afterward, you’ll receive a clear recommendation on which vector database is right for you.
As an AI partner for small and medium-sized businesses, we’ll get your vector database up and running—including ingest pipelines, permissions, monitoring, and evaluations.
What We Offer
- RAG Consulting & Implementation — Vector databases as the backbone of productive AI solutions.
- AI Integration — Seamless integration with CRM, ERP, DMS, and knowledge management systems.
- AI Workshop — Which architecture, database, and approach are right for you.
- Resource Library: White Papers & Guides — Practical knowledge on AI architectures available for download.