I published a comparison of Azure SQL, Cosmos DB, and Blob Storage a little while back. Looking back at it, Azure Table Storage was a real gap - it sits in a genuinely useful middle position between a relational table and a full document database, and it deserves its own proper explanation rather than a passing mention. This post fills that in, with real C# code and a few lessons from using it in production alongside Azure Service Bus at Blue Yonder.
What Azure Table Storage Actually Is
Azure Table Storage is a NoSQL key-value store for large amounts of structured, non-relational data. It occupies an interesting middle position - simpler and considerably cheaper than Cosmos DB, while still being schema-flexible in a way Azure SQL fundamentally is not. Despite the name, it has nothing to do with SQL tables in the relational sense - "table" here is closer to a giant, partitioned dictionary than a database table with fixed columns.
Azure SQL is a filing cabinet with identical forms in every folder.
Cosmos DB is a box of index cards where every card can say something different.
