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<?xml version="1.0" encoding="ISO-8859-1"?>
<!--
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- project.
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- Copyright (C) 1998-2018 OpenLink Software
-
- This project is free software; you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published by the
- Free Software Foundation; only version 2 of the License, dated June 1991.
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-->
<refentry id="fn_XMLType.getRootElement">
<refmeta>
<refentrytitle>XMLType.getRootElement</refentrytitle>
<refmiscinfo>xml</refmiscinfo>
</refmeta>
<refnamediv>
<refname>XMLType.getRootElement</refname>
<refpurpose>Returns top-level element of the given instance (NULL for fragment)</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis id="fsyn_XMLType.getRootElement">
<funcprototype id="fproto_XMLType.getRootElement">
<funcdef><function>XMLType.getRootElement</function></funcdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 id="desc_XMLType.getRootElement">
<title>Description</title>
<para>If the given instance is well-formed then this function will return
the top-level element of the document that is stored within the instance.
If the given instance is a fragment then NULL will be returned because there
may be no top-level elements or too many of them.</para>
<para>Note that in spite of this functions name this function actually
returns the a top-level node rather than not a root node. According to the
W3C XPATH standards, the root element is an implicit node whose children are top-level
elements, comments, processing instructions and maybe text nodes. E.g. if
a correct HTML document is started by tag <computeroutput><HTML></computeroutput>
and ended by corresponding <computeroutput></HTML></computeroutput> tag
then the only top-level node is the "<computeroutput>HTML</computeroutput>"
element node and this node is a single child of the root node.</para>
<para>If the given instance is well-formed then the function returns a
top-level element of the document that is stored in the instance. If the
given instance is fragment then NULL is returned, because there may be
no top-level elements or too many of them.</para>
<para>If the given instance is schema-based then the returned
instance is based on the same schema.</para>
</refsect1>
<refsect1 id="ret_XMLType.getRootElement"><title>Return Types</title>
<para>The function returns an XMLType instance.</para>
</refsect1>
<refsect1 id="examples_XMLType.getRootElement">
<title>Examples</title>
<example id="ex_XMLType.getRootElement"><title>A table with an XMLType column</title>
<para>First select statement lists well-formed documents; second one lists the only fragment in the table.</para>
<screen><![CDATA[
create table TEST_XMLS (I integer primary key, XMLVAL XMLType);
insert into TEST_XMLS values (1, XMLType('<emp><empno>221</empno><ename>John</ename></emp>'));
insert into TEST_XMLS values (2, XMLType('<po><pono>331</pono><poname>PO_1</poname></po>'));
insert into TEST_XMLS values (3, XMLType('<oil-rig id="14a" water="0.413"/><oil-rig id="14b" water="0.402"/>'));
select e.I, e.XMLVAL.getRootElement().getClobVal()
from TEST_XMLS as e
where e.XMLVAL.getRootElement() is not null
I callret
INTEGER NOT NULL NVARCHAR
_______________________________________________________________________________
1 <emp><empno>221</empno><ename>John</ename></emp>
2 <po><pono>331</pono><poname>PO_1</poname></po>
2 Rows. -- 00000 msec.
select e.I, e.XMLVAL.getClobVal()
from TEST_XMLS as e
where e.XMLVAL.getRootElement() is null
I callret
INTEGER NOT NULL NVARCHAR
_______________________________________________________________________________
3 <oil-rig id="14a" water="0.413" /><oil-rig id="14b" water="0.402" />
1 Rows. -- 00000 msec.
]]>
</screen>
</example>
</refsect1>
<refsect1 id="seealso_XMLType.getRootElement">
<title>See Also</title>
<para><link linkend="fn_XMLType.isFragment"><function>XMLType.isFragment()</function></link></para>
</refsect1>
</refentry>
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