Author: jstephens
Date: 2006-01-17 14:58:23 +0100 (Tue, 17 Jan 2006)
New Revision: 866
Log:
xml-functions:
- Added a couple more limitations.
- Added some more general info about XPath expressions.
Modified:
trunk/refman-5.1/functions.xml
Modified: trunk/refman-5.1/functions.xml
===================================================================
--- trunk/refman-5.1/functions.xml 2006-01-17 13:44:45 UTC (rev 865)
+++ trunk/refman-5.1/functions.xml 2006-01-17 13:58:23 UTC (rev 866)
@@ -11226,9 +11226,10 @@
<para>
This function takes two string arguments, a fragment of XML
markup <replaceable>xml_frag</replaceable> and an XPath
- expression <replaceable>xpath_expr</replaceable>, and returns
- the value matched by <replaceable>xpath_expr</replaceable>.
- Note that <literal>ExtractValue()</literal> returns only the
+ expression <replaceable>xpath_expr</replaceable> (also known
+ as a <firstterm>locator</firstterm>), and returns the value
+ matched by <replaceable>xpath_expr</replaceable>. Note that
+ <literal>ExtractValue()</literal> returns only the
<literal>CDATA</literal> that is contained directly by the tag
matching <replaceable>xpath_expr</replaceable>, and does not
return any tags that might be contained within the matching
@@ -11448,6 +11449,16 @@
root element.
</para>
</listitem>
+
+ <listitem>
+ <para>
+ Multiple locators may be matched using the
+ <literal>|</literal> (logical <literal>OR</literal>) operator.
+ For example, the expression <literal>//b|//c</literal> matches
+ all <replaceable>b</replaceable> and
+ <replaceable>c</replaceable> elements in the XML target.
+ </para>
+ </listitem>
<listitem>
<para>
@@ -11471,6 +11482,16 @@
element <literal><b c="x" d="y"/></literal> occurring
anywhere in a given XML fragment.
</para>
+
+ <para>
+ To find elements for which the same attribute matches one of
+ several values, you must use multiple locators joined by the
+ <literal>|</literal> operator. For example, to match all
+ <replaceable>b</replaceable> elements whose
+ <replaceable>c</replaceable> attributes have either of the
+ values 23 or 17, use the expression
+ <literal>//b[@c="23"]|b[@c="17"]</literal>.
+ </para>
</listitem>
</itemizedlist>
@@ -11480,8 +11501,9 @@
scope of this Manual. Please see the
<ulink url="http://www.w3.org/TR/xpath">XML Path Language (XPath)
1.0 standard</ulink> for definitive information. A useful resource
- for those new to XPath or wishing a refresher in the basics is the
- <ulink url="http://www.zvon.org/xxl/XPathTutorial/">Zvon.org XPath
+ for those new to XPath or who are wishing a refresher in the
+ basics is the
+ <ulink url="http://www.zvon.org/xxl/XPathTutorial/">Zvon.org XPath
Tutorial</ulink>, which is available in several languages.
</para>
@@ -11499,9 +11521,25 @@
comparisons of the form
<literal>[@<replaceable>attribute</replaceable>="<replaceable>const</replaceable>"]</literal>,
where <replaceable>const</replaceable> is a constant value,
- are currently possible.
+ are currently possible. Note that equality and inequality
+ (<literal>=</literal> and (<literal>!=</literal>)) are the
+ only supported comparison operators.
</para>
</listitem>
+
+ <listitem>
+ <para>
+ Relative locator expressions are not supported. XPath
+ expressions must begin with <literal>/</literal> or
+ <literal>//</literal>.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ The <literal>::</literal> operator is not supported.
+ </para>
+ </listitem>
<listitem>
<para>
| Thread |
|---|
| • svn commit - mysqldoc@docsrva: r866 - trunk/refman-5.1 | jon | 17 Jan |
