A system for defining a plurality of extended tables, wherein each extended table of the plurality of extended tables is associated with a corresponding base table of a plurality of base tables. The system updates data contained by the plurality of extended tables in accordance with data contained by the plurality of base tables, wherein the updating is performed asynchronously across logical units of data contained by the plurality of extended tables. The system provides a combined view of the data contained by the plurality of extended tables and the data contained by the plurality of base tables.