SQL Server is a relational database management system (RDMS) first developed by Sybase, Ashton-Tate, and Microsoft in the late 1980s and through the early 1990s. It started as an RDMS for non-Microsoft computers until version 4.2. Microsoft ultimately purchased the rights to the code and focused on making it a fully integrated product for their systems. By SQL Server 2005, all legacy code had been replaced or rewritten.

While SQL Server is the number one RDMS for business applications in the world, it is not heavily used in web based applications. SQL server is a proprietary RDMS that works natively in Microsoft enviroments. There are two primary, Microsoft proprietary, query languages that work with a SQL Server. It was designed primarily for business applications and for Microsoft environments that require a lot of updating and information changes in data. SQL Server does not have a free version like MySQL, but SQL Server has strong feature updating, security management, and bug fixing support.

There are, at this time, 12 different types of SQL Server. The 12 types range from a single user on a single computer, to what they call “Big Data” versions, which are applications that require the ability to support large numbers of users accessing large amounts of data simultaneously. Microsoft has been developing SQL Server to be more capable of handling large web applications and databases, as well as data warehousing.

Microsoft’s most recent version, SQL Server 2012, supports in-memory technology, clusters, Always on Availability, creating multiple instances of databases, and several other speed and failover technologies.

SQLServer has some technical and programming differences from other SQL RMDSs in how data is managed and accessed. The easiest explanation of the difference between SQL Server and other RMDS’ is to liken it to a dialect of the SQL language. Each SQL RMDS is written for SQL, but each RMDS uses slightly different paradigms based on their intended uses, the user’s environment, operating systems, and target market. Each RMDS thus has different ways of performing some functions, and will typically either lack functions that other RMDSs use or have functions that won’t translate to another RMDS. For instance, SQL supports XML where some other RMDSs do not.