The field specifies either numerical attribute combinations consisting of type=value pairs separated by comma (e.g.
where field1 specifies primary attributes for sort, field2 seconds, etc.. The field specifies either numerical attribute combinations consisting of type=value pairs separated by comma (e.g. 1=4,2=1); or the field may specify a plain string criteria (e.g. title. The flags is a sequnce of the following characters which may not be separated by any white space.