Database handle for the object. It is of XML type ID, so is constrained to beunique in the XML document within which it occurs. An external identifier for the object inthe form of a URI may be constructed using standard XML and XPointer methods. This is doneby concatenating the URI for the document, a fragment separator, and the value of the idattribute.
Source
<element name="Equipment" type="diggs:EquipmentType" substitutionGroup="diggs:AbstractEquipment" abstract="false"><annotation><documentation>Generic equipment that carries only the properties of the base type. Use it where a more specialized equipment object is not needed or not developed.</documentation></annotation></element>