21. The method of claim 2 , further comprising selectively identifying an object of the cumulative schema as a map.
21. The method of claim 2 , further comprising selectively identifying an object of the cumulative schema as a map. 27. The method of claim 21 , further comprising storing a datum corresponding to the map into an auxiliary map index as a key-value pair, wherein the value of the key-value pair is the datum, and wherein the key of the key-value pair is based on (i) a path of the datum consistent with the relational schema, (ii) a map key of the datum in the map, (iii) a unique identifier of a first object of the retrieved objects, wherein the first object provided the datum, and (iv) a join key of the map.