This element can be used in the following different contexts:

1. For reference definition, the tsd:refers element is used in the context of tsd:standard or tsd:text as described in the following table:

   Purpose	This element defines references for use in connection with reference indexes. The content of the tsd:refers element specifies the node that is to be used as a base for a reference. For more information on this topic, see also tsd:reference and tsd:which.
   Parent element	tsd:text, tsd:standard
   Child elements	None
   Attributes	None
   Restrictions	The following rules apply for this element: The element that describes the index (in the contents of the accompanying tsd:which element) must have a parent that matches the XPath expression of the <tsd:refers> value. Otherwise an error message is issued. In the example below, an additional <tsd:which>/Doc/A/B/X/C</tsd:which> would also match, but a <tsd:which>/Doc/A/X/C</tsd:which> would cause an error at define time. Only absolute path expressions that do not contain any wildcards are supported in this context. The option for the tsd:structureIndex element may not be "none". As long as these conditions are fulfilled, recursive structures can also be indexed.
   Type	xs:string

   Example

   This example shows how to use the tsd:refers element for index definition: The index refers to /Doc/A/B.

   <xs:element name = "C" type = "xs:string">
   ...
      <tsd:elementInfo>
        <tsd:physical>
          <tsd:which>/Doc/A/B/C</tsd:which>
          <tsd:native>
            <tsd:index>
              <tsd:text>
                <tsd:refers>/Doc/A/B<tsd:refers>
              </tsd:text>
            </tsd:index>
          </tsd:native>
        </tsd:physical>
   ...
   </xs:element>
   

2. For reference index definition, the tsd:refers element is used in the context of tsd:reference as described in the following table:

   Purpose	In the context of reference indexes, one reference node may refer to another reference node. The current reference node uses the tsd:refers element to specify the reference node. For more information on this topic, see also tsd:reference and tsd:which.
   Parent element	tsd:reference
   Child elements	None
   Attributes	None
   Restrictions	The following rules apply for the contents of this element: The element that describes the index (in the contents of the accompanying tsd:which element) must have a parent that matches the XPath expression of the <tsd:refers> value. Otherwise an error message is issued. In the example below, an additional <tsd:which>/Doc/A/B/X/C</tsd:which> would also match, but a <tsd:which>/Doc/A/X/C</tsd:which> would cause an error at define time. Only absolute path expressions that do not contain any wildcards are supported in this context.
   Type	xs:string

   Example

   The following excerpt from a schema describes a reference index definition for the node B, which should refer to the ancestor /Doc/A:

   <xs:element name = "B" maxOccurs = "unbounded">
     .
     .
     .
     <tsd:elementInfo>
       <tsd:physical>
         <tsd:native>
           <tsd:index>
             <tsd:reference>
               <tsd:refers>/Doc/A<tsd:refers>
             </tsd:reference>
             .
             .
             .
           </tsd:index>
         </tsd:native>
       </tsd:physical>
     </tsd:elementInfo>
     .
     .
     .
   </xs:element>