Author: jstephens
Date: 2007-11-29 14:38:08 +0100 (Thu, 29 Nov 2007)
New Revision: 8977
Log:
Updated discussion of 5.1/6.0 XPath support (Thanks, Bar!):
| = logical UNION, not OR
logical or can be used inside predicates
relative paths are supported, including within predicates
Modified:
trunk/refman-5.1/functions-core.xml
trunk/refman-6.0/functions-core.xml
Modified: trunk/refman-5.1/functions-core.xml
===================================================================
--- trunk/refman-5.1/functions-core.xml 2007-11-29 13:07:30 UTC (rev 8976)
+++ trunk/refman-5.1/functions-core.xml 2007-11-29 13:38:08 UTC (rev 8977)
Changed blocks: 3, Lines Added: 59, Lines Deleted: 11; 3875 bytes
@@ -13559,11 +13559,11 @@
<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.
+ You can match any of several locators using the
+ <literal>|</literal> (<literal>UNION</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>
@@ -13591,14 +13591,24 @@
</para>
<para>
- To find elements for which the same attribute matches one of
- several values, you must use multiple locators joined by the
+ To find elements for which the same attribute matches any of
+ several values, you can 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>.
+ <literal>//b[@c="23"]|//b[@c="17"]</literal>. You can also use
+ the logical <literal>or</literal> operator for this purpose:
+ <literal>//b[@c="23" or @c="17"]</literal>.
</para>
+
+ <note>
+ <para>
+ The difference between <literal>or</literal> and
+ <literal>|</literal> is that <literal>or</literal> joins
+ conditions, while <literal>|</literal> joins result sets.
+ </para>
+ </note>
</listitem>
</itemizedlist>
@@ -13645,10 +13655,48 @@
<listitem>
<para>
- Relative locator expressions are not supported. XPath
- expressions must begin with <literal>/</literal> or
- <literal>//</literal>.
+ Relative locator expressions are resolved in the context
+ of the root node. For example, consider the following
+ query and result:
+
+<programlisting>
+mysql> <userinput>SELECT ExtractValue(</userinput>
+ -> <userinput>'<a><b c="1">X</b><b c="2">Y</b></a>',</userinput>
+ -> <userinput>'a/b'</userinput>
+ -> <userinput>) AS result;</userinput>
++--------+
+| result |
++--------+
+| X Y |
++--------+
+1 row in set (0.03 sec)
+</programlisting>
+
+ In this case, the locator <literal>a/b</literal> resolves
+ to <literal>/a/b</literal>.
</para>
+
+ <para>
+ Relative locators are also supported within predicates. In
+ the following example, <literal>d[../@c="1"]</literal> is
+ resolved as <literal>/a/b[@c="1"]/d</literal>:
+
+<programlisting>
+mysql> <userinput>SELECT ExtractValue(</userinput>
+ -> <userinput>'<a></userinput>
+ -> <userinput><b c="1"><d>X</d></b></userinput>
+ -> <userinput><b c="2"><d>X</d></b></userinput>
+ -> <userinput></a>',</userinput>
+ -> <userinput>'a/b/d[../@c="1"]')</userinput>
+ -> <userinput>AS result;</userinput>
++--------+
+| result |
++--------+
+| X |
++--------+
+1 row in set (0.00 sec)
+</programlisting>
+ </para>
</listitem>
<listitem>
Modified: trunk/refman-6.0/functions-core.xml
===================================================================
--- trunk/refman-6.0/functions-core.xml 2007-11-29 13:07:30 UTC (rev 8976)
+++ trunk/refman-6.0/functions-core.xml 2007-11-29 13:38:08 UTC (rev 8977)
Changed blocks: 3, Lines Added: 59, Lines Deleted: 11; 3875 bytes
@@ -13500,11 +13500,11 @@
<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.
+ You can match any of several locators using the
+ <literal>|</literal> (<literal>UNION</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>
@@ -13532,14 +13532,24 @@
</para>
<para>
- To find elements for which the same attribute matches one of
- several values, you must use multiple locators joined by the
+ To find elements for which the same attribute matches any of
+ several values, you can 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>.
+ <literal>//b[@c="23"]|//b[@c="17"]</literal>. You can also use
+ the logical <literal>or</literal> operator for this purpose:
+ <literal>//b[@c="23" or @c="17"]</literal>.
</para>
+
+ <note>
+ <para>
+ The difference between <literal>or</literal> and
+ <literal>|</literal> is that <literal>or</literal> joins
+ conditions, while <literal>|</literal> joins result sets.
+ </para>
+ </note>
</listitem>
</itemizedlist>
@@ -13583,10 +13593,48 @@
<listitem>
<para>
- Relative locator expressions are not supported. XPath
- expressions must begin with <literal>/</literal> or
- <literal>//</literal>.
+ Relative locator expressions are resolved in the context
+ of the root node. For example, consider the following
+ query and result:
+
+<programlisting>
+mysql> <userinput>SELECT ExtractValue(</userinput>
+ -> <userinput>'<a><b c="1">X</b><b c="2">Y</b></a>',</userinput>
+ -> <userinput>'a/b'</userinput>
+ -> <userinput>) AS result;</userinput>
++--------+
+| result |
++--------+
+| X Y |
++--------+
+1 row in set (0.03 sec)
+</programlisting>
+
+ In this case, the locator <literal>a/b</literal> resolves
+ to <literal>/a/b</literal>.
</para>
+
+ <para>
+ Relative locators are also supported within predicates. In
+ the following example, <literal>d[../@c="1"]</literal> is
+ resolved as <literal>/a/b[@c="1"]/d</literal>:
+
+<programlisting>
+mysql> <userinput>SELECT ExtractValue(</userinput>
+ -> <userinput>'<a></userinput>
+ -> <userinput><b c="1"><d>X</d></b></userinput>
+ -> <userinput><b c="2"><d>X</d></b></userinput>
+ -> <userinput></a>',</userinput>
+ -> <userinput>'a/b/d[../@c="1"]')</userinput>
+ -> <userinput>AS result;</userinput>
++--------+
+| result |
++--------+
+| X |
++--------+
+1 row in set (0.00 sec)
+</programlisting>
+ </para>
</listitem>
<listitem>
| Thread |
|---|
| • svn commit - mysqldoc@docsrva: r8977 - in trunk: refman-5.1 refman-6.0 | jon | 29 Nov |
