Object id = idField.getFromTarget(obj);
if (id == null) return null;
List<?> res = field.getManager().getByQualification(field.getConfig().target(),
"$db." + field.getConfig().target().getSimpleName() + "." + tar + "$ = $id$",
new AttributeMap("id", id) ).toCacheAndClose();
if (res != null && res.size() > 0)
relation = (T) res.get(0);
// relation = (T) field.getManager().getObject(field.getConfig().target(), id);