Relational Query Planning for Non-Relational Data Sources

A query plan for executing a query within a relational database system including at least one non-relational data source is generated by analyzing expressions that reference a non-relational data source within a query for the database system via an interface for that non-relational data source, determining for each analyzed expression at least one of the database system and interface capable of processing that analyzed expression for executing the query, providing an indicator for each of the analyzed expressions that indicates at least one of the database system and interface determined to process that analyzed expression, and generating the query plan for execution of the query, via the database system, based on the indicators for the expressions of the query.