Abstract: A database processor is provided for on-line analytical processing. The processor is arranged to obtain multi-dimensional aggregates of an input relation. Prior to aggregation, the processor performs a pre-processing stage in which the processor identifies Group-bys that are equivalent to the root relation and thus can be derived directly from the root relation without computation. In this manner, the computational time and storage of the multidimensional aggregates is reduced since only unique Group-bys in the lattice are computed and stored.

Abstract: A database processor for on-line transaction processing has significantly reduced storage. The processor is arranged to obtain multi-dimensional aggregates of an input relation after a pre-processing stage which identifies aggregates which can be obtained without computation, said pre-processing stage being arranged to: i) identify and store the primary keys derived from the schema of the input relation; ii) establish a Group-by schema generator to generate schemas from minimum arity to maximum arity of aggregate for the possible aggregates of the input relation; iii) sequentially in an arity order beginning with single columns and proceeding in an order in which each lower level of every sub-tree is visited before any root (i.e.