Language-Integrated Querying of XML Data in SQL Server

Developers need to access persistent XML data programmatically. Object-oriented access is often the preferred method. Translating XML data into objects or vice-versa is a hard problem due to the data model mismatch and the difficulty of query translation. The prototype addresses this problem by transforming object-based queries and updates into queries and updates on XML using declarative map-pings between classes and XML schema types. The proto-type extends the ADO.NET Entity Framework and lever-ages its object-relational mapping capabilities. The authors demonstrate how a developer can interact with stored relational and XML data using the Language Integrated Query (LINQ) feature of .NET. The authors show how LINQ queries are translated into a combination of SQL and XQuery. Finally, they illustrate how explicit mappings facilitate data in-dependence upon database refactoring.