Identify duplicate tags in Xml using XQuery/schema

Question

I have an Xml fragment where I need to verify that there is only a single ocurrence of each node on the first level (0-based).

An example of bad Xml is this:

<library>
  <book1>
    <title>My first book</title>
    <PageNum>101</PageNum>
  </book1>
  <book2>
    <title>My second book</title>
  </book2>
  <book1>
    <title>Another of my first book</title>
  </book1>
  <book3>
    <title>My third book</title>
    <PageNum>101</PageNum>
  </book3>
</library>

... since there are two ocurrences of elements with element name "book1" at the first level.

The structure of the child-nodes is not important - just that there are no nodes with the same "top-level" element name. I also do not know the names of the child nodes.

How do I do this - using RelaxNg, XSD or XQuery?

Thanks, Jesper

dirkk dirkk · Accepted Answer · 2015-05-28T07:42:00

Using XPath/XQuery you can compare whether the length of a sequence of all the tag names is of equal length than the length of a sequence of all distinctive tag names:

count(*/name()) = count(distinct-values(*/name()))

Identify duplicate tags in Xml using XQuery/schema

1 Answers