Approaches herein transparently delegate data access from a relational database management system (RDBMS) onto an offload engine (OE). The RDBMS receives a database statement referencing a user defined function (UDF). In an execution plan, the RDBMS replaces the UDF reference with an invocation of a relational operator in the OE. Execution invokes the relational operator in the OE to obtain a result based on data in the OE. Thus, the UDF is bound to the OE, and almost all of the RDBMS avoids specially handling the UDF. The UDF may be a table function that offloads a relational table for processing. User defined objects such as functions and types provide metadata about the table. Multiple tables can be offloaded and processed together, such that some or all offloaded tables are not materialized in the RDBMS. Offloaded tables may participate in standard relational algebra such as in a database statement.