Data wareh。 use Vs。 Heter。 geneous DBMS Traditional heterogeneous DB integration a query driven approach Build wrappers/mediators on top of heterogeneous databases When a query is posed to a client site a meta-dictionary is used to translate the query into queries appropriate for individual heterogeneous sites involved and the results are integrated into a global answer set Complex information filtering compete for resources Data warehouse: update-driven, high performance Information from heterogeneous sources is integrated in advance and stored in warehouses for direct query and analysis9 Data Warehouse vs. Heterogeneous DBMS ◼ Traditional heterogeneous DB integration: A query driven approach ◼ Build wrappers/mediators on top of heterogeneous databases ◼ When a query is posed to a client site, a meta-dictionary is used to translate the query into queries appropriate for individual heterogeneous sites involved, and the results are integrated into a global answer set ◼ Complex information filtering, compete for resources ◼ Data warehouse: update-driven, high performance ◼ Information from heterogeneous sources is integrated in advance and stored in warehouses for direct query and analysis