Name
xml_namespace_scope — Returns a vector of all namespace declarations in all ancestors of the given XML entity.
Synopsis
vector
xml_namespace_scope
(
|
in ent XML Entity , |
in
use_default_ns
integer
); |
Description
The function returns a vector of even length that consists of all declared namespace prefixes and namespace URIs
from the ent
and all its ancestors. This information is needed for processing XML documents that
contains a mix of data and XPath expressions, such as BPEL documents.
Parameters
ent
The entity to process.
use_default_ns
Flags if the resulting array should contain declarations of default namespace. If it is zero then only declarations of namespace prefixes are listed; if non-zero then all declarations are listed.
Return Types
The function returns a vector of even length that contains narrow strings in UTF-8 encoding.
Examples
Example 24.515. Adding namespace declarations to the XPath expression
The function gets an entity whose string-value is an XPATH expression and returns the text of expression with all namespace declarations that are in scope. The resulting expression is context-independent. This is useful for BPEL-like applications and for extracting XPATH expressions from XML Schema documents.
create procedure xpath_add_namespace_scope (in ent any, in use_default_ns integer)
{
declare _expn varchar;
declare _ses any;
declare _scope any;
declare _ctr any;
_expn := charset_recode (xpath_eval ('string(.)', ent), '_WIDE_', 'UTF-8');
_scope := xml_namespace_scope (ent, use_default_ns);
_ctr := length (_scope);
if (_ctr = 0)
return _expn;
_ses := string_output ();
http ('[', _ses);
while (_ctr > 0)
{
if (_scope[_ctr-2] = '')
http (sprintf (' xmlns="%s"', _scope[_ctr-1]), _ses);
else
http (sprintf (' xmlns:%s="%s"', _scope[_ctr-2], _scope[_ctr-1]), _ses);
_ctr := _ctr - 2;
}
http (' ] ', _ses);
http (_expn, _ses);
return string_output_string (_ses);
}
select xpath_add_namespace_scope (
xquery_eval (
'declare namespace xsd="http://www.w3.org/2001/XMLSchema";
//xsd:keyref[@name="ISBNnumber"]/xsd:field/@xpath',
xtree_doc (
'<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
targetNamespace="http://www.publishing.org"
xmlns="http://www.publishing.org">
<xsd:element name="Book" minOccurs="1" maxOccurs="unbounded">
<xsd:keyref name="ISBNnumber" refer="BookDB_ISBN">
<xsd:selector xpath="."/>
<xsd:field xpath="ISBN"/>
</xsd:keyref>
</xsd:element>
<!-- The rest of the XML Schema file is skipped -->
</xsd:schema>')),
1 );
callret
VARCHAR
_______________________________________________________________________________
[ xmlns="http://www.publishing.org" xmlns:xsd="http://www.w3.org/2001/XMLSchema" ] ISBN