What is the name of Microsoft's relational database management system?

Microsoft’s relational database management system is Microsoft SQL Server. It is a database server developed by Microsoft that stores, organizes, and retrieves structured information for software applications, websites, businesses, and other services.

SQL Server uses Structured Query Language, or SQL, for interacting with data. Microsoft also provides its own extended dialect called Transact-SQL, commonly abbreviated T-SQL. Alongside tables, queries, and indexes, SQL Server supports features such as stored procedures, views, transaction logs, security controls, reporting, and high-availability configurations.

The product’s roots reach back to a 1989 project involving Microsoft and Sybase to bring a SQL database server to OS/2. SQL Server 4.2 for Windows NT followed in 1993, and Microsoft ended its collaboration with Sybase during the development of SQL Server 6.0 in 1995. Later versions increasingly became Microsoft’s own codebase and platform.

SQL Server is sometimes confused with Microsoft Access, but Access is primarily a desktop database application, while SQL Server is a server-oriented relational database management system. It also differs from PostgreSQL, MySQL, and Oracle Database, which are competing database systems made by other organizations. Microsoft offers SQL Server in editions aimed at developers, small deployments, enterprises, and cloud workloads.