MS SQL Server is a relational database management system developed by Microsoft. As a database server, its primary function is to store and retrieve data as requested by other software applications, be it those on the same computer or those running on another computer across a network
It supports a number of storage engines. The default engine since SQL Server 2012 is based on In-Memory OLTP technology. The other two engines are Merge and Hekaton. All three engines have their own specialities and specifications; for example, In-Memory OLTP's main strength is high performance with small data sets and low memory requirements, while Hekaton's main strength