Microsoft SQL Server is a relational database management system build on top of SQL programming language. Just like most database systems, the SQL server is built on a row-based table structure that connects elements from different tables. The main purpose of SQL Server is storing and retrieving of information from the local or remote computer.
Microsoft SQL Server usually isn’t available for free, but you can get the Developer or the Express version for free, but bear in mind that these versions have certain limitations. The Developer version has the same features as the Enterprise Edition, but it’s limited only to testing purposes. The Express version includes the core database engine and it’s limited to one processor, 1GB of memory, and 10GB of storage.