xquery-path-expressions

          child::Features
        

XQuery path expressions locate nodes, such as element, attribute, and text nodes, in a

document. The result of a path expression always occurs in document order without duplicate

nodes in the result sequence. In specifying a path, you can use either unabbreviated or

abbreviated syntax. The following information focuses on the unabbreviated syntax.

Abbreviated syntax is described later in this topic.

A path expression can be relative or absolute. Following is a description of both of these:

A relative path expression is made up of one or more steps separated by one or two slash

marks (/ or //). For example,

is a relative path expression, where

refers only to child nodes of the context node. This is the node that is currently being

processed. The expression retrieves the element node children of the context

node.

An absolute path expression starts with one or two slash marks (/ or //), followed by an

optional, relative path. For example, the initial slash mark in the expression,

, indicates that it is an absolute path expression. Because a

slash mark at the start of an expression returns the document root node of the context

node, the expression returns all the element node children of the

document root.

If an absolute path starts with a single slash mark, it may or may not be followed by a

relative path. If you specify only a single slash mark, the expression returns the root node

of the context node. For an XML data type, this is its document node.

A typical path expression is made up of steps. For example, the absolute path expression,

,contains two steps separated by a slash mark.

The first step retrieves the element node children of the document

root.

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Note

Because the sample queries in this topic are specified against the

type columns,

and

, in the

table, you should familiarize

yourself with the contents and structure of the XML documents stored in these columns.

child::Features
Child
/child::ProductDescription
/child::ProductDescription/child::Summary