使用FLWOR从所选节点中删除xml子元素

Question

I'm trying to remove the "number" child element with: @tsip:form="wila" from the "applications" node below using a flwor query. The data is in an Oracle 11g database, in a xml_type column, Oracle uses xquery 1.0. I've managed to accomplish this below but my attempt is very clumsy and long winded as I have hard coded the intermediate elements between the parent "applications" element and the child "number" element , so if the format of the xml changes my query may not work. Can anyone offer a more generic solution. It must be easier than this:

Create a table:

CREATE TABLE XML_DOCUMENT_TMP
(
  DOCUMENT_ID   NUMBER(12)                      NOT NULL,
  XML_DATA      SYS.XMLTYPE                     NOT NULL,
  CREATED_DATE  TIMESTAMP(6)                    NOT NULL
);

Insert some data into XML_DOCUMENT_TMP:

insert into XML_DOCUMENT_TMP
(document_id,created_date,xml_data)
values(6,sysdate,'<patent  xmlns="http://schemas.xx.com/ts/20041221/tsip" 
xmlns:tsip="http://schemas.xx.com/ts/20041221/tsip" 
tsip:action="replace" tsip:cc="CA" tsip:se="2715340" tsip:ki="C">
<keepThis>data</keepThis>
<applications tsip:action="new">
    <application tsip:cc="GB" tsip:se="2338695" tsip:ki="A" tsip:priorityCode="A2">
        <applicationId>
            <number tsip:form="wila">9813397</number>
            <number tsip:form="original">9813397</number>
            <number tsip:form="tsip">000013397</number>
            <countryCode>GB</countryCode>
            <applicationYear>1998</applicationYear>
            <date>1998-06-23</date>
        </applicationId>
    </application>
</applications>
<keepThis2>data2</keepThis2>
</patent>
');

Select all the data except the "number" element with @tsip:form="wila"

SELECT /*+ NO_XML_QUERY_REWRITE */ xA.document_id ,
XMLSerialize(DOCUMENT
    XMLQuery('xquery version "1.0";
      declare default element namespace  "http://schemas.xx.com/ts/20041221/tsip";
      declare namespace  tsip="http://schemas.xx.com/ts/20041221/tsip";

       <patent xmlns="http://schemas.xx.com/ts/20041221/tsip"   xmlns:tsip="http://schemas.xx.com/ts/20041221/tsip" >{$a/*:patent/@*}   
      {

         for $s in $a/*:patent/*
            return 

            if ($s = $a/*:patent/applications) 
            then    
              <applications>{$a/*:patent/applications/@*}
                <application>{$a/*:patent/applications/application/@*}
                  <applicationId> 
                  {
                    (: Use the "except" clause to remove the unwanted <number> element with the "wila" attribute value :)
                    $a/*:patent/applications/application/applicationId/* except $a/*:patent/applications/application/applicationId/number[@tsip:form="wila"] 
                  }          
                </applicationId>
              </application>
            </applications>
          else $s   
      }
      </patent>'
            PASSING xA.xml_data as "a"  
            RETURNING CONTENT) ) newXml 
 FROM XML_DOCUMENT_TMP xA            
WHERE document_id=6;

Answer 1

In XQuery you can use a recursive function to visit each node and test if that node should be removed. If it should be removed, you do nothing, if it should not be removed you make a copy of it as a new node with the same name element {node-name(.)} { ... and continue visiting its children:

declare namespace  tsip="http://schemas.xx.com/ts/20041221/tsip";
declare function local:transform($root) {
  $root / (typeswitch (.)
   case element(tsip:number) return 
     if (@tsip:form = "wila") then ()
     else .
   case element() return 
      element {node-name(.)} { 
        @*, for $n in node() return local:transform($n)
      }
   default return .
  )
};
local:transform($a)