docs: function pg_create_index_name(self, ObjType, type, field, typefield) {
  	var name;
  	var colname = _parse_predicate_key(ObjType, {'epoch':false}, field);
  	var datakey = colname.getMeta('datakey');
  	var field_name = (datakey ? datakey + '.' : '' ) + colname.getMeta('key');
  	if( (ObjType === NoPg.Document) && (typefield !== undefined)) {
  		if(!typefield) {
  			throw new TypeError("No typefield set for NoPg.Document!");
  		}
  		name = pg_convert_index_name(ObjType.meta.table) + "_" + typefield + "_" + pg_convert_index_name(field_name) + "_index";
  	} else {
  		name = pg_convert_index_name(ObjType.meta.table) + "_" + pg_convert_index_name(field_name) + "_index";
  	}
  	return name;
  }