17. A computer readable storage medium, comprising executable instructions to: receive a query specification; receive a semantic abstraction associated with the query specification, wherein the semantic abstraction represents data source entities to be retrieved from an underlying data source; compute an execution plan, wherein the executable instructions to compute the execution plan comprise executable instructions to: evaluate the query specification to identify one or more of the data source entities to be retrieved; determine relationships between the data source entities; group data source entities into sets of compatible data source entities based on logical relationships between the data source entities; process operation instructions required by the query specification; and execute the execution plan, wherein the executable instructions to execute the execution plan comprise executable instructions to: retrieve a data flow associated with the query specification from a data source driver; and assemble the data flows into a query result set; and provide the query result set.
30. The computer readable storage medium of claim 17 wherein the executable instructions to receive an entity relationship model associated with the query further comprise executable instructions to parse the query to determine which entity relationship model to retrieve and to retrieve the entity relationship model.