Some embodiments provide a non-transitory machine-readable medium that stores a program executable by at least one processing unit of a device. The program provides, through a graphical user interface (GUI), a tool for creating a field calculation that operates on data defined in a relational data model. The program also receives, through the GUI, the field calculation created using the tool. The program further generates data for a data integration operation based on the field calculation. The program also performs the data integration operation based on the generated data.