Unique constraint in XML Schema

Question

Let\'s say I have following XML file:

   a1
   a2
   2010         


        

Answer 1

The selector XPath selects the nodes that must be unique (in that case, it should select the author nodes).

The field XPath selects what "makes them unique" (in that case, using . will cause their typed value, in that case the text between the tags, treated as a string, to be used).

The document

  a1
  a2
  2010-01-01

should be valid against the following schema:

while this one should not:

  a1
  a1
  2010-01-01