16. The computer-readable volatile or non-volatile medium of claim 12 , wherein: the instructions that cause storing said each materialized view further comprise instructions which, when executed by the one or more processors, cause: determining a set of unique disjuncts from the first one or more disjuncts in the set of aggregate expressions included in the definition of said each materialized view; and storing, in the set of disjunct trees, information that identifies the set of unique disjuncts determined for said each materialized view; and the instructions that cause determining the particular materialized view from the plurality of materialized views comprise instructions which, when executed by the one or more processors, cause: comparing the second one or more disjuncts in the disjunct tree to the set of unique disjuncts determined for said each materialized view of the plurality of materialized views; selecting, in a set of candidate materialized views, all materialized views from the plurality of materialized views that are associated with sets of unique disjuncts that include all of the second one or more disjuncts; for each candidate view of the set of candidate materialized views: generating a canonical form closure that includes expression representations of all combinations of disjuncts in the set of unique disjuncts associated with said each candidate view; and comparing the aggregate expression to the expression representations in the canonical form closure of said each candidate view; and from the set of candidate materialized views, selecting as the particular materialized view a candidate view whose canonical form closure includes an expression representation that matches the aggregate expression.
16. The computer-readable volatile or non-volatile medium of claim 12 , wherein: the instructions that cause storing said each materialized view further comprise instructions which, when executed by the one or more processors, cause: determining a set of unique disjuncts from the first one or more disjuncts in the set of aggregate expressions included in the definition of said each materialized view; and storing, in the set of disjunct trees, information that identifies the set of unique disjuncts determined for said each materialized view; and the instructions that cause determining the particular materialized view from the plurality of materialized views comprise instructions which, when executed by the one or more processors, cause: comparing the second one or more disjuncts in the disjunct tree to the set of unique disjuncts determined for said each materialized view of the plurality of materialized views; selecting, in a set of candidate materialized views, all materialized views from the plurality of materialized views that are associated with sets of unique disjuncts that include all of the second one or more disjuncts; for each candidate view of the set of candidate materialized views: generating a canonical form closure that includes expression representations of all combinations of disjuncts in the set of unique disjuncts associated with said each candidate view; and comparing the aggregate expression to the expression representations in the canonical form closure of said each candidate view; and from the set of candidate materialized views, selecting as the particular materialized view a candidate view whose canonical form closure includes an expression representation that matches the aggregate expression. 17. The computer-readable volatile or non-volatile medium of claim 16 , wherein the canonical form closure for said each candidate view includes ∑ i = 1 n ⁢ 2 i ⁢ ( n i ) number of expression representations, wherein “n” indicates the number of aggregate expressions in the set of aggregate expressions associated with said each candidate view.