XQuery in XML with namespace

Question

I am using eXist-DB to store XML documents. Here is an example XML file with namespace information:

<?xml version="1.0" encoding="utf-8"?> <ClinicalDocument xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="urn:hl7-org:v3"> <name> <family>Smith</family> <middle>Blade</middle> <first>John</first> </name> <name> <family>Frost</family> <middle>Bill</middle> <first>Conrad</first> </name> </ClinicalDocument> 

Request:

 declare namespace xsd = "http://www.w3.org/2001/XMLSchema"; declare namespace xsi = "http://www.w3.org/2001/XMLSchema-instance"; for $x in doc("/db/HL7/cda2.xml")/ClinicalDocument/name return $x/family 

I tried to declare a third namespace in the query, but it does not work.

Answer 1

The third namespace attribute (xmlns = "urn: hl7-org: v3") binds the default namespace.

The syntax for defining a default namespace for elements in XQuery is:

 declare default element namespace "urn:hl7-org:v3"; 

However, overriding the default element namespace prevents your query from being validated for nodes without a namespace!

The best way to do this is to possibly associate a new prefix with this namespace:

 declare namespace xsd = "http://www.w3.org/2001/XMLSchema"; declare namespace xsi = "http://www.w3.org/2001/XMLSchema-instance"; declare namespace h17 = "urn:h17-org:v3"; for $x in doc("/db/HL7/cda2.xml")/h17:ClinicalDocument/h17:name return $x/h17:family