Microsoft SQL Server

Microsoft SQL Server is Microsoft's relational database management system. An application connects to a SQL Server instance or a database and sends Transact-SQL, usually called T-SQL. The Database Engine receives the request, checks access, and reads or changes data.

Think in layers. An instance is the running Database Engine. It can host several databases. A database groups tables, views, stored procedures, users, and other objects for one application or workload. A table stores rows in typed columns. Schemas group database objects and provide a namespace.