Abstract: A query engine or compute engine receiving a query request identifies a plurality of data sources for satisfying a query request, and determines, from among multiple data sources, one or more fields likely to incur substantial computational demands in processing the query request. Pre-positioning aggregation logic moves the determined fields one data source to another data source for positioning the moved fields to a single data source from which the query result will be computed.

Abstract: A data query and retrieval system receives a query request and identifies a plurality of data warehouses, or stores, where data needed to satisfy the query is stored. Data items, or fields, called for by the query request are grouped into sets based on fields stored at the same data warehouse. Individual data connections are generated for each data warehouse accessed, and a database view defined for the fields available at each respective data warehouse. The individual views are invoked in a single query statement by a query processor for accessing the respective data warehouses via the corresponding database view. In this manner, a query operator or user need not define multiple query expressions or perform separate queries for accessing data fields or dimensions residing at different data warehouses.

Abstract: A query engine or compute engine receiving a query request identifies a plurality of data sources for satisfying a query request, and determines, from among multiple data sources, one or more fields likely to incur substantial computational demands in processing the query request. Pre-positioning aggregation logic moves the determined fields one data source to another data source for positioning the moved fields to a single data source from which the query result will be computed.