Schematron: Officer Has a Last Name

This is the first in a series of code example articles that will be posted to give NIEM developers a head start in using Schematron. This example will show how to perform a test across multiple branches or nodes of a typical NIEM schema as law enforcement officer is a role played by a person in NIEM schemas. Take the following example XML code:

<ns:SomeDocument>
<j:Citation>  
   <j:CitationIssuingOfficial>
     <nc:RoleOfPersonReference s:ref="P1"/>  
   </j:CitationIssuingOfficial>
</j:Citation>
<nc:Person s:id="P1">
   <nc:PersonName><nc:PersonSurName>Smith</nc:PersonSurName></nc:PersonName>
</nc:Person>
</ns:SomeDocument>

One way in which to test for the existence of a last name is to match the ID with the officer's REF and test to be sure the string length is greater than 1 as shown in the following example (using XSLT2 & ISO Schematron):

<pattern id="eOfficerData"> 
    <let name="sOfficerRef" value="ns:SomeDocument/j:Citation/ j:CitationIssuingOfficial/nc:RoleOfPersonReference/@s:ref"/> 
    <rule context="ns:SomeDocument/nc:Person"> 
        <report test="@s:id = $sOfficerRef and string-length(nc:PersonName/nc:PersonSurName) < 1"> 
            Officers last name must be provided. 
        </report> 
    </rule> 
</pattern>

In theory the same test can be done using the XQuery id() function however use of the id function is HIGHLY dependent on the parser's capabilities.