Download the code for this article: SQLXML3.exe (239KB)
SUMMARY XML is becoming the ubiquitous data format on the Web, and XML support in SQL Server is evolving to meet the additional demand. Using XML, SOAP, HTTP, and SQL Server, you can now build powerful Web Services easily. To show just how simple it is with SQLXML 3.0, this article walks the reader through the process step by step, from setting up a virtual directory enabling data access via HTTP to executing queries and building Web Services. Finally, the author illustrates the creation of two Web Services clients梠ne with C# that works with the Microsoft .NET Framework and one with the SOAP Toolkit 2.0 for anyone still using earlier development tools.
t's hard to believe that XML support in SQL Server?2000 has been around for over two years. In the software world, that's a lifetime. SQL Server 2000 was the first version to provide native support, and this was limited to the more basic XML feature set (template queries, mapping schemas, and OPENXML). Using simple HTTP queries you could retrieve formatted relational data in XML format. With a little help and some Extensible Stylesheet Language (XSL) magic, you could spit out the data in a formatted, HTML-friendly manner. Later, with the introduction of features like updategrams, you could easily submit an XML-based SQL template to insert or update rows of information in SQL Server with little effort.
Initially, I thought that some would consider XML support a frivolous addition to an already powerful product. If a developer wasn't displaying SQL data in a Web page or feeding a system that only speaks XML, were these features all that useful?Previously, the only viable approach for accessing data, for the middle-tier anyway, was through a traditional data access layer built with ODBC, OLE DB, or ADO. Now with SQLXML 3.0, SQL Server 2000, SOAP, BizTalk? and the .NET Framework, XML is no longer a frivolous addition梚t's the data language of choice.
Using SQLXML 3.0 for Data AccessSQLXML 3.0 is the third iteration of XML support for SQL Server. The biggest difference between the old way of representing data and the way it's represented with XML is how the rowset is created, where it is created (server-side or client-side), and how it is formatted (raw, nested, element-based, or attribute-based). For more on raw and explicit formats, refer to the information listed in the article summary.For those of you already working with some of the .NET server products such as BizTalk, managed classes, and the like, you already know how important it is to use XML as your data format. If using XML for data access is new to you, this may take some getting used to. If you choose to use XML as your data format, you must take into account the subtle differences between relational and hierarchical representation and how you can exploit the benefits of a hierarchy.If you are upgrading from a previous version, you can still run SQLXML 3.0
