1. A computer-implemented method to generate code from a data flow associated with an extract, transform, and load (ETL) process, the computer implemented method comprising: converting the data flow into a logical operator graph representing the data flow and including a plurality of operators corresponding to a sequence of operations defined by the data flow for the associated ETL process, the plurality of operators including first and second operators representing data transformation steps in the data flow, wherein the first and second operators are associated with first and second types of runtime engine, respectively, wherein the logical operator graph is in turn converted into a query graph model; analyzing at least one of the logical operator graph and the query graph model in order to identify a data exchange requirement between the first and second operators from the data flow; modifying at least one of the data flow, the logical operator graph, and the query graph model based on the identified data exchange requirement and including inserting a data station operator between the first and second operators from the data flow, the data station operator representing a staging point in the data flow operable to exchange data from a format associated with the first type of runtime engine to a format associated with the second type of runtime engine; and subsequent to inserting the data station operator between the first and second operators from the data flow, generating an execution plan graph from the query graph model and by operation of one or more computer processors, including generating, based on the inserted data station operator, code to manage data staging between the first and second operators from the data flow.