Hello, Colleagues ! I have a table with geographical objects, every object has set of semantic values. Thus we have object-semantic relation one-to-many. Tables structure was
objects id_object | id_semantic 1 2 1 3 1 4 ... n n1 n n2 semantics id_semantic semantic_value 2 1.6 3 4.0 ... n1 'ppp' ... I have to select objects without semantics from list or if this semantic is set then its has to be satisfy defined condition e.g. select id_object from (objects as o inner join semantics as s on (2 not in (select id_semantic from objects as os where os.id_object=o.id_object) )); List of semantic conditions is not limited, therefore execution time will be arise. What kind of optimization may be applied, for tables and queries ? Thanks a lot. -- Best regards, Sincerely yours, Yuriy Rusinov
