Database choice in Azure usually comes down to Azure SQL or Cosmos DB. The two solve very different problems. The wrong choice brings bad results in both performance and cost.
01. Azure SQL: Relational
The cloud-adapted form of Microsoft SQL Server. ACID transactions, complex SQL queries, a mature ecosystem. The right choice for most enterprise applications.
02. Cosmos DB: Global NoSQL
Cosmos DB is a globally distributed NoSQL database. 99.999% uptime SLA, single-digit millisecond latency. Strong in multi-region scenarios.
03. Cosmos DB API Options
Cosmos DB supports multiple APIs:
- SQL API (native)
- MongoDB API (for Mongo migration)
- Cassandra API
- Gremlin API (graph)
- Table API (simple key-value)
04. Use Cases
A short guide:
- Classic business applications: Azure SQL
- High traffic, low latency: Cosmos DB
- Globally distributed customers: Cosmos DB
- Complex reporting, join-requiring analysis: Azure SQL
05. Price Difference
Azure SQL is usually more economical. Cosmos DB's power comes at a cost; it isn't needed in every scenario. At small scale, for standard business apps, Cosmos DB is overkill.