METHOD FOR PROVIDING A SYSTEM MAINTAINED MATERIALIZED FUNCTIONALLY DEPENDENT COLUMN FOR A DATABASE MANAGEMENT SYSTEM

摘要

A mechanism for supporting generated materialized columns without explicitly adding triggers and a check constraint in a database management system (DBMS). When a column affecting the generated materialized column is updated, a "before-update" trigger is internally generated in the DBMS and added as the last trigger before the update occurs. Similarly, when an insert operation is performed, a "before-insert" trigger is generated internally by the DBMS and added as the last trigger before the insert operation occurs. Since the triggers are generated internally in the DBMS, a constraint is not needed for either the update or the insert operations.