xqueryxquery-update

XQuery Update - Add new node to group nodes

I have an XML file with following structure - 

<Root>
   <Doc>
    <Ref>
      <A></A>
      <B></B>
      <A></A>
      <B></B>
      <B></B>
      <B></B>
    </Ref>
   </Doc>  
   <Doc>
    <Ref>
      <A></A>
      <B></B>
      <B></B>
      <B></B>
    </Ref>
   </Doc>  
   <Doc>
    <Ref>
      <A></A>
      <B></B>
      <B></B>
      <A></A>
      <B></B>
      <B></B>
    </Ref>
   </Doc>  
</Root>

The node A and all simultaneous nodesB needs to grouped like

<Root>
   <Doc>
    <Ref>
      <data>
        <A></A>
        <B></B>
      </data>
      <data>          
        <A></A>
        <B></B>
        <B></B>
        <B></B>
      </data>
    </Ref>
   </Doc>  
   <Doc>
    <Ref>
      <data>
       <A></A>
       <B></B>
       <B></B>
       <B></B>
      </data>     
    </Ref>
   </Doc>  
   <Doc>
    <Ref>
      <data>
       <A></A>
       <B></B>
       <B></B>
      </data>
      <data>   
       <A></A>
       <B></B>
       <B></B>
      </data>    
    </Ref>
   </Doc>  
</Root>

The number of nodes B, after node A can be anything, like 2, 3 ... or 10..

Solution

  • The best way to process such structures is with a 'tumbling window clause'. This will nicely organize the data in the groups that you want. I'll leave it up to you to figure out the exact xquery-update syntax required.

    for $ref in //Ref
return <Ref>{
  for tumbling window $w in $ref/element()
    start $s when $s/self::A
  return <data>{$w}</data>
  }</Ref>