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Demystifying Vector Databases: A Practical Guide

February 7, 2026

Vector databases are everywhere in AI applications, but the terminology can be overwhelming. Here's a practical, no-nonsense guide.

Demystifying Vector Databases: A Practical Guide

If you're building anything with LLMs, you've probably heard about vector databases. Let's cut through the jargon.

What's a Vector, Anyway?

In this context, a vector is just a list of numbers that represents the meaning of a piece of text.

When Do You Actually Need a Vector DB?

You need one when:

  • Building RAG systems
  • Implementing semantic search
  • Finding similar items

You probably don't need one when:

  • Your dataset is small (< 10k items)
  • You only need keyword search

My Recommendation

Start with ChromaDB for prototyping, graduate to pgvector if you're already using PostgreSQL.