Explaining the 5 types of database and how to choose between them

What database should you choose? Worse, what kind of database should you choose?

My aim is to give you enough information to make that choice, or at least be aware of what the alternatives are.

I'd argue that there are five important database types at the moment, differing in how they regard the "shape" of their data. I'll give a brief introduction to each, explaining how it works, and discuss why you might want to use that particular type of database, depending on your data and what you want to do with it. I'll show case at least one open source example of each.

I'll cover:

• Relational (PostgreSQL®, SQLite)
• Columnar (ClickHouse®)
• Document (OpenSearch®)
• Key Value (Valkey™️)
• and as an extra, Graph (Neo4J®)

The slides are available at https://github.com/Aiven-Labs/the-5-types-of-database