Microsoft SQL Server is a database management system which was launched in 1989 by Microsoft. The system is able to retrieve and store data which has been requested by other software applications, such as those which are running on the same computer or applications from another network, such as the internet.
In total, there are at least twelve different versions of SQL Server, with each edition aimed at a different audience, and serving different functions, such as internet-facing applications with various users, and smaller single-machine applications. The primary languages used are ANSL SQL and T-SQL.
SQL Server 2012
The most recent version of the system is SQL Server 2012, which includes AlwaysOn, allowing users to replicate more than one database. You can keep a database at a remote site, or locally for quick failover. These replicas can be readable, unlike in the database mirroring process.
SQL Server Express is a free version of the system provided by Microsoft, and works with numerous web application frameworks such as Drupal, PHP and Wordpress. The free database software is available with a number of different extensions, including various reporting options, and the Microsoft Migration Assistant provides technical guidance to new users and advice on how to make the most out of the program. SQL Server Express can be download for free from the Microsoft website.
The future of SQL Server
SQL Server 2014 is still in the preview stage, but will incorporate in-memory capability of tables. Although small tables are already present in memory in later versions of SQL Server, they reside on disk, and work has been ongoing to reserve ram, load pages from the disk, and lock pages in ram when they are being worked on.
There are also a number of specialized editions of SQL Server, including SQL Azure Database, a cloud-based version of the system.