An On-Line Analytic Processing (OLAP) system computes complex expressions and aggregations in queries by re-using and sharing subparts of the expressions and aggregations. A dependency generation phase performed by the OLAP system identifies dependencies among metrics based on the expressions, aggregations,...http://www.google.ca/patents/US6567804?utm_source=gb-gplus-sharePatent US6567804 - Shared computation of user-defined metrics in an on-line analytic processing system
