In which cases is reference partitioning effective in enhancing performance?()  
A: It is effective only in partition pruning.
B: It is effective only in partitionwise joins provided that the query predicates are different from the partitioning key.
C: It is effective in both partition pruning as well as partitionwise joins provided that the query predicates are identical to the partitioning key.
D: It is effective in both partition pruning as well as partitionwise joins irrespective of whether the query predicates are different from or identical to the partitioning key.
出自:Oracle认证