What Are Vector Databases?

How they store embeddings and enable similarity search for unstructured data

Overview

Vector databases store numerical representations of data—called embeddings—and use them to perform fast similarity search across unstructured content such as text, images, audio, and more.

Vector DB Graphic

Key Concepts

Embeddings

Dense vector representations capturing meaning and relationships in unstructured data.

Vector Indexes

Specialized data structures enabling fast similarity search, such as IVF, HNSW, and PQ.

Similarity Metrics

Distance functions (cosine, Euclidean, dot-product) used to measure vector closeness.

How Vector Databases Work

1

Data (text, images, audio) is converted into embeddings using an AI model.

2

Embeddings are stored in a vector index optimized for similarity search.

3

A query is transformed into a vector and compared against indexed vectors.

4

The database returns the closest vectors, representing the most relevant results.

Common Use Cases

Vector DBs vs Traditional Databases

Traditional DBs

  • Store structured records
  • Use exact match queries
  • Not built for similarity search

Vector DBs

  • Store high-dimensional embeddings
  • Perform approximate nearest-neighbor search
  • Handle unstructured data efficiently

FAQ

Do vector databases store raw data?

Some do, but most store embeddings and optionally link back to the original content.

Are vector searches exact?

They use approximate nearest neighbor (ANN) algorithms for speed and scalability.

What models generate embeddings?

Large language models, image encoders, audio models, and domain-specific embedding models.

Explore Vector Databases Further

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