Oracle Database 11g Building Oracle XML DB Applications

XQuery Beyond the Basics

XQuery can perform complex operations. Let’s look at some examples.

Using Functions

We have used some functions in the previous examples. In Listing 8-1, we used empty() and not() functions in the where clause to select contacts with non-empty emails using not(empty($email)). In Listings 8-7 and 8-8, we used fn:doc() and fn:collection() to retrieve documents from XML DB Repository and relational tables. There are many other functions defined by W3C XQuery 1.0 and XPath 2.0 standards, which we can use to perform different operations. Please refer to the Oracle XML DB Developer’s Guide and W3C Standards to learn more about the available functions.

Nested XQuery Expressions

XQuery expressions can be more complex than FLWOR ...