The term "SQL Server" is most commonly associated with the official name of Microsoft's relational database management system. However, SQL server is broadly defined as any database server that uses the SQL programming language. Microsoft SQL Server is one of several relational database servers that uses the SQL language.
Two computer scientists -- Donald D. Chamberlain and Raymond F. Boyce -- developed SQL in 1974 for manipulating and retrieving data from IBM's System R database platform. Back then, the language was called SEQUEL, which stood for Structured English QUEry Language. However, IBM had to change the acronym to SQL, or Structured Query Language, because Hawker Siddley, an aircraft company based in the U.K., had already trademarked "SEQUEL." In 1979, Oracle Corp. became the first company to base its relational database software on SQL.
Current Status and Major Players
Today, SQL is the industry standard for relational database servers. As of 2013, Oracle had the largest market share with its Oracle Database platform, while IBM's DB2 and Microsoft SQL Server rounded up the top three.