[xquery-talk] Xquery+ reduce two docs into one

[James A. Robinson]

> I am quite new to xquery and I have a FLWOR question

So am I, so take this with a large grain of salt.  Most of my recent
XQuery experience hasn't been at the target domain of the language,
join operations!  So anyway, here is one solution (I think):


(: Get metadata from documents :)
let $m1   := doc("sebi-1.xml")/*/meta
let $m2   := doc("sebi-2.xml")/*/meta
(: determine common FileName by textual value :)
let $intersect := (
  let $common := (
  for $f in ($m1/FileName, $m2/FileName)
    where (($f = ($m1/FileName)) and ($f = $m2/FileName))
    return $f
  )
  return (
    for $name in distinct-values($common)
    return $common[. = $name][1]
  )
)
return
<FF>
  <meta>{
    (: for each meta with an intersecting FileName :)
    for $m in ($m1, $m2)
    where ($intersect = $m/FileName)
    return
      (: return the meta elements which are not FileName :)
      $m/*[not(self::FileName)],
    (: return the FileName intersect :)
    $intersect
  }</meta>
</FF>

This returns

<?xml version="1.0" encoding="UTF-8"?>
<FF>
   <meta>
      <Value2>2.8</Value2>
      <Value1>7.90mm</Value1>
      <FileName>file7</FileName>
      <FileName>file8</FileName>
      <FileName>file9</FileName>
      <FileName>file14</FileName>
      <FileName>file15</FileName>
      <FileName>file16</FileName>
      <FileName>file17</FileName>
      <FileName>file18</FileName>
      <FileName>file19</FileName>
   </meta>
</FF>


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James A. Robinson                       jim.robinson at stanford.edu
Stanford University HighWire Press      http://highwire.stanford.edu/
+1 650 7237294 (Work)                   +1 650 7259335 (Fax)