Persistent storage contains a parent table and one or more child tables, the parent table containing: a class field specifying types, and one or more filter fields. One or more processors may: receive a first request to read first information of a first type for a first entity; determine that, in a first entry of the parent table for the first entity, the first type is specified in the class field; obtain the first information from a child table associated with the first type; receive a second request to read second information of a second type for a second entity; determine that, in a second entry of the parent table for the second entity, the second type is indicated as present by a filter field that is associated with the second type; and obtain the second information from a set of additional fields in the second entry.