MySQL is a relational database management system (RDBMS) which has more than 11 million installations. The program runs as a server providing multi-user access to a number of databases.
MS SQL Server
It is a relational model database server produced by Microsoft. Its primary query languages are T-SQL and ANSI SQL
SQL Server 2005
SQL Server 2005 included native support for managing XML data, in addition to relational data. For this purpose, it defined an XML data type that could be used either as a data type in database columns or as literals in queries. XML columns can be associated with XSD schemas.
SQL Server 2008
The current version of SQL Server, SQL Server 2008, aims to make data management self-tuning, self organizing, and self maintaining with the development of SQL Server Always On technologies, to provide near-zero downtime. SQL Server 2008 also includes support for structured and semi-structured data, including digital media formats for pictures, audio, video and other multimedia data.
The Oracle Database (commonly referred to as Oracle RDBMS or simply Oracle) is a relational database management system (RDBMS) produced and marketed by Oracle Corporation. As of 2009 Oracle remains a major presence in database computing.
It is the most advanced open source database. It is a powerful object related database system. It has more than 15 years of active development and a proven architecture that has earned it a strong reputation for reliability, data integrity, and correctness. It runs on all major operating systems, including Linux, UNIX and Windows. It has native programming interfaces for C/C++, Java, .Net, Perl, Python, Ruby, Tcl, ODBC, among others, and exceptional documentation.