An XPath expression allows you to locate a node (an element with its ramifications) in the hierarchical tree structure of an XML document.
The XPath expressions permitted to define constraint selectors and fields are limited to a subset of the full XPath language defined in the W3C Recommendation XML Path Language 1.0:
|
Syntax |
Description |
|---|---|
|
/ |
Root node of the XML document. It is the root element with its ramifications |
|
. |
Selects the context node. It is the current element (on which an identity constraint is defined) with its ramifications |
|
.. |
Selects the context node parent |
|
* |
Selects all the child elements of the context node |
|
employee |
Selects all the employee child elements of the context node |
|
s:employee |
Selects all the employee child elements of the context node, defined in the namespace with the "s" prefix |
|
@numEmployee |
Selects the numEmployee attribute of the context node |
|
@* |
Selects all the attributes of the context node |
|
../@numEmployee |
Selects the numEmployee attribute of the context node parent |
|
employee[1] |
Selects the first employee child element of the context node |
|
employee[last()] |
Selects the last employee child element of the context node |
|
*/employee |
Selects all the employee grandchildren of the context node |
|
//employee |
Selects all the employee descendants of the root node |
|
.//employee |
Selects the employee descendants of the context node |
|
company//employee |
Selects the employee descendants of the company child elements of the context node |
|
//company/employee |
Selects all the employee elements with company as parent element in the context node |
|
/book/chapter[2]/section[3] |
Selects the third section in the second chapter of the book |
|
employee[@dept="doc"] |
Selects all the employee child elements of the context node with a dept attribute set to doc |
|
employee[@dept="doc"][3] |
Selects the third employee child element of the context node with a dept attribute set to doc |
|
employee[3][@dept="doc"] |
Selects the third employee child element of the context node only if it has a dept attribute set to doc |
|
chapter[title] |
Selects the chapter child elements of the context node with at least one title child element |
|
chapter[title="About this book"] |
Selects the chapter child elements of the context node with at least one title child element with a text content set to About this book |
|
employee[@numEmployee and @dept] |
Selects all the employee child elements of the context node with the numEmployee and dept attributes |
|
text() |
Selects all the child nodes of the text context node |