Systems, methodologies, media, and other embodiments associated with supporting materialized views with user-defined aggregates are described. One example system includes logic for exposing a set of interface actions to support a user-defined aggregate in a materialized view associated with a base table. The materialized view may store both the user-defined aggregate and a user-defined aggregate context that facilitates logically connecting the user-defined aggregate to the base table. The example system may also include logic for supporting the user-defined aggregate. The support may be based on the set of interface actions. Example systems and methods may, therefore, facilitate incremental updating of the materialized view and/or rewriting a query to access the materialized view.