How Vector Databases Work

The Technology Powering RAG, AI Search, and Semantic Retrieval

Arvind Kumar

8 min read

·

May 19, 2026

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Most developers spend years working with traditional databases.

You learn:

• SQL
• indexing
• joins
• transactions
• exact-match queries

And over time, your brain develops a certain mental model of how search works.

Example:

SELECT * 
FROM courses
WHERE title = 'Spring Boot'

The database searches exact values.
Exact keywords.
Exact matches.

This approach powered software systems for decades.

But modern AI applications introduced a completely different problem.

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Humans rarely search using exact keywords.

Instead, we search using:

• meaning
• intent
• similarity
• context

For example:

How can I build scalable Java APIs?