//-- process field(s)
String ELEM_FIELD = schemaPrefix + SchemaNames.FIELD;
Enumeration enumeration = constraint.getFields();
while(enumeration.hasMoreElements()) {
IdentityField field = (IdentityField) enumeration.nextElement();
_atts.clear();
id = field.getId();
xpath = field.getXPath();
_atts.addAttribute(SchemaNames.XPATH_ATTR, CDATA, xpath);
if (id != null) {
_atts.addAttribute(SchemaNames.ID_ATTR, CDATA, id);
}
_handler.startElement(ELEM_FIELD, _atts);