XQuery 1.0 and XPath 2.0 Data Model, xdt:yearMonthDuration</a>.</p>
 
 <p>The datatype <code>xdt:yearMonthDuration</code> is a subtype of <code>xs:duration</code>
 whose lexical representation contains only year and month components.
 This datatype resides in the namespace <A HREF="../../../javax/xml/XMLConstants.html#W3C_XPATH_DATATYPE_NS_URI"><CODE>XMLConstants.W3C_XPATH_DATATYPE_NS_URI</CODE></A>.</p>
 
 <p>Both values are set and availabe from the created <A HREF="../../../javax/xml/datatype/Duration.ht