SQL Server code base grew out of the product owned by Sybase. The version for OS/2 release in 1989 was a product owned by Microsoft. By the time SQL Server version was released in 2000 the code base was nearly free of Sybase code. The SQL Server code for version 2005 was entirely of Microsoft. Typically, SQL Server version 2005 and the subsequent ones have been released in different editions. These are the Express, Standard, Enterprise and Business Intelligence (new in 2012 version) editions.
A recommended strategy for adoption of SQL Server 2005 and other versions is to get started with the Express edition. This is entirely free to use and even redistribute as part of any product/application you may have developed. The SQL 2005 introduced a new data type XML. A table column may be defined as of the XML data thus ensuring XML data can be stored in the SQL Server 2005 database. XML strings also could be used as literals where appropriate. XML data required specialized indexing and were made available in the SQL 2005. T-SQL extensions were also introduced so that XQuery based XML data queries could be embedded in T-SQL. XQuery is the language for querying a collection of XML data. With XML becoming a native type of the database, SQL 2005 onwards, the database acquired the capability to collaborate through web services. Results returned by participating services are returned as XML data. Several other new features in SQL Server 2005 were introduced to help with scaling, error handling and performance. Dynamic Management Views or DMVs help viewing the state of the database server to monitor a database instance, diagnose problems as they happen or to tweak it performance. Data mirroring support in SQL Server products appeared first with this 2005 version. Data redundancy became part of the server. On failure, it was easy to recover by simply switching over to the mirrored data. Switching manually or automatically is supported in SQL 2005.
SQL Server 2005 Express module edition is available from several sources besides the Microsoft. The download module is quite easy to download quickly and get it installed and running quickly. Updating the product automatically helps keep the SQL Server 2005 updated to the latest security levels and the most current feature list. The SQL Server 2005 Express also works seamlessly with Visual Studio Express editions for quick developments of Windows and web applications. Moving or copying the Express database to a different server or a computer is quite simple.
In summary, then, SQL Server 2005 is a true MS owned product. This is expected to offer scalability, performance and data safety improvements. Introduction of the XML data type ensures it is able to participate in web service’s arrangements. Easy deployment and the ease of application development through integration with Visual Studio are a couple of other notable features. Management features of the SQL 2005 makes configuring the product fairly automatic. If you are just starting off to use RDBMS and do not plan to use the additional features of the later 2008, 2008 r2 and 2012 or the upcoming 2014 versions, the SQL Server 2005 Express is a good point to start.