Microsoft SQL Server is a database server.
It is a program that runs on a Server and returns answers to database
queries. Applications that need data from a database query the SQL Server with
a request for some information and the SQL Server replies with the results of
the request. 
SQL Server is typically used as the database engine for applications
that either require large amounts of data to be stored within the database
or have many users who want access to the database at the same time.
SQL Server comes with tools to automatically back up the data, recover from
failures and has sophisticated security to limit individual users
privileges. SQL Server is usually used in businesses to house their mission
critical data.
Oracle, Pervasive and MySQL are database engines available from other vendors
with similar features to SQL Server.
Key Strengths of SQL Server
-
Speed
- SQL Server is a dedicated database engine tuned to quickly returning
the results of database queries.
-
Robustness
- SQL Server is designed to manage and protect mission critical
data.
-
Multiple Users- SQL Server can comfortably handle multiple
requests for data at the same time.
-
Security and Administration - SQL Server comes with a rich set
of tools and user security options.
