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Sreekar Reddy
Sreekar Reddy

Posted on • Originally published at sreekarreddy.com

🔮 Vector DBs Explained Like You're 5

Finding needles in a haystack by meaning

Day 34 of 149

👉 Full deep-dive with code examples


The Library Problem

You need a book about "feeling sad."

Traditional database: Searches for exact words "feeling sad."
Finds nothing! (Book is called "Understanding Depression")

Vector database: Searches by MEANING.
Finds "Understanding Depression" because it's ABOUT feeling sad!


How It Works

Remember embeddings? They turn words into numbers.

"Feeling sad" → [x1, x2, x3, ...]
"Understanding Depression" → [y1, y2, y3, ...]

These numbers are CLOSE together = similar meaning!

Vector DB finds vectors close to your query.


Regular DB vs Vector DB

Regular DB Vector DB
Search by exact match Search by similarity
"Find users named Alex" "Find docs similar to this"
Keywords Meaning

Used For

  • 🔍 Semantic search
  • 🤖 RAG (AI with documents)
  • 🎵 Similar song/product recommendations
  • 🖼️ Image similarity

Popular Vector DBs

Pinecone, Weaviate, Chroma, Milvus


In One Sentence

Vector databases store and search data by meaning, not just exact words, using mathematical representations (embeddings).


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