Selecting a database platform

Within Azure, there are two main types of database—Azure Cosmos DB and Azure SQL. There are also several different kinds of SQL databases—Azure SQL Database, Azure SQL Managed Instance, or even traditional Microsoft SQL running on a virtual machine (VM). In this section, however, we will consider why you might choose Cosmos DB over SQL Server.

With the choice between Cosmos DB and SQL and a choice between relational SQL databases and hierarchical NoSQL databases, we need to understand the differences between them. We will start with SQL.

Understanding SQL databases

SQL databases are built around the concept of tables, and within each table, you would have rows of data split into cells. Each cell would contain an individual piece of data within a record, and each row would be an entire record.

SQL databases have a schema that lays out your data structure in tables, columns, and rows. The schema must be defined before you can enter data...