SQL Server 2005(Yukon) specialities & .NET Integration and What It Does for You

The most evident change in Yukon is a far greater integration with the .NET Framework. The current versions of SQL Server 2000 are accessible via CLR-hosted assemblies, but the DBMS engine itself is not integrated with .NET. As a result, multi-tiered deployment involves bridging technologies like ADO.NET, and database coding is constrained to Microsoft's own SQL dialect, Transact-SQL (aka T-SQL). In contrast, Yukon will host a CLR directly in the DBMS engine, meaning that code written in C#, VB.NET, and other .NET languages can be executed by SQL Server. (This is in addition to Transact-SQL.)
Given the greater expressiveness of C# and VB.NET, this feature will greatly facilitate coding, and it will remove the requirement that programmers learn advanced features of SQL to perform straightforward tasks. In fact, should they wish to, developers can code stored procedures, triggers, and user-defined functions (UDFs) entirely in .NET languages. Microsoft uses the System.Data.SqlServer namespace to provide this .NET access to SQL Server. (Readers who are members of Microsoft's MSDN network can download beta versions of Yukon and the needed .NET files from the MSDN website to begin testing this functionality.)
Yukon will also be better integrated with Microsoft's flagship IDE, Visual Studio .NET. While this environment supports the .NET languages well, SQL Server and T-SQL are not exactly first-class citizens with the plenary support enjoyed by C# and VB.NET. The new version of SQL Server aims to correct this by being more tightly integrated with Visual Studio (via plug-ins) so as to provide better support for T-SQL and XML, and by adding support for OLAP technologies, such as XML for Analysis (XML/A, an OLAP and business intelligence interface) and Multidimensional Expression (MDX, a syntax for querying multidimensional data in SQL Server). In addition, Visual Studio .NET 2005 (code-named Whidbey) is slated to include a set of advanced reporting controls for Yukon.
Notification Service
A problem that pervades all database development is the question of the currency of the data: Has the data I am using been updated? This question underlies data-locking schemes, two-phased commits, and almost all important database activities.One infrequently discussed activity where this problem is a chronic nuisance is data cached by applications themselves, specifically Web applications. Why cache the data if it has to be reread each time to make sure no update has occurred?This question is addressed directly in Yukon by a new notification service. In its simplest form, this enables developers to identify certain commands to SQL Server by use of a notification tag. This notification requests that the database inform the application anytime that running the same command would generate different results. In this way, applications that cache data can simply query this notification (which is stored in a queue) and determine whether a data refresh is warranted.
Expanded XML Support
Previous versions of SQL Server supported XML via the use of "shredding," which is the parsing of XML tag components into the corresponding relational table columns. Yukon supports XML natively. Although, it will not become a true XML database (a category that is a specialty niche), Yukon will offer a native XML data type. This enhancement lifts XML from the category of "bunch of strings" to a type with which unique activities are associated. For example, SQL Server 2005 will enable queries to portions of an XML document, validation of the document against an XML schema, and even modification of the XML document in place. As for the underlying representation, the XML data is stored as a binary large object (BLOB), which enables the database to perform compression whenever possible.Queries against XML data can be performed using XML Query (XQuery), which is an evolving specification from the W3C often used in conjunction with XPath. Yukon will implement the statically typed subset of this "SQL of XML," based on the W3C's working draft of November 15, 2003.
Web Services—
Dramatic ImprovementYukon's support for Web services is a dramatic improvement over previous releases. Notably, the DBMS engine will serve as an HTTP listener. This functionality means that Web services can be developed in the database tier and accessed without a middle tier listener such as IIS. Literally send the HTTP SOAP request to a URL which is listened to by SQL Server and you can execute ad hoc T-SQL commands. For every listener, SQL Server 2005 sets up a separate URL, so it is possible to expose many Web services directly from the database engine.This innovation means that SQL Server can be accessed without recourse to ODBC, JDBC, or ADO. Consequently, it will be particularly attractive to sites that use Web services to integrate disparate databases. And it will be especially useful for applications that run on intermittently connected endpoints (such as handheld devices) and which need quick connect capabilities.(The HTTP listener capability, by the by, is currently supported only on Windows Server 2003 due to the need for the specific HTTP driver that comes with that version of the operating system.)