1. A data processing method comprising: processing a table definition composed in a domain-specific language, the table definition comprising a sequence of one or more dataset transformations to be performed on one or more source tables to generate a target table; retrieving an intermediate table that was generated based on performing a first dataset transformation of the one or more dataset transformations on a previous version of a particular source table of the one or more source tables; generating a supplemental portion for the intermediate table based on performing a second dataset transformation on an appended portion of an updated version of the particular source table; generating the target table based on performing a third dataset transformation on the intermediate table and the supplemental portion for the intermediate table; wherein the method is performed by one or more computing devices.