A system and method for facilitating querying one or more data sources. A system provides mechanisms to enable flexible specification of user queries and generation of one or more SQL queries that correspond closely to corresponding user queries. An operator tree and a logical operator tree may be created as intermediate steps to generate the one or more SQL queries. Capabilities of data sources are determined and used to generate remotable SQL queries for composable queries, to reduce an amount of post-processing that is performed on result sets. The system enables user queries that extend beyond those defined by a data model.