11. A computer system comprising: one or more processors; one or more non-transitory data storage media coupled to the one or more processors and storing instructions which, when executed by the one or more processors, cause: 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.
11. A computer system comprising: one or more processors; one or more non-transitory data storage media coupled to the one or more processors and storing instructions which, when executed by the one or more processors, cause: 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. 20. The system of claim 11 , wherein the one or more storage media further comprise sequences of instructions which when executed cause storing one or more references to the one or more source tables at a server computer, without corresponding copies of the one or more source tables being stored at the server computer.