Derivation of incremental equations for nested relations

Incremental equations form an important method for incrementally maintaining materialized views. We derive incremental equations for the general nested relational model, a data model in which incremental equations have not been derived to the best of our knowledge and a data model which is used in warehouses and in XML data. We derive incremental equations based on two types of nested relational algebra, non-recursive and recursive. We then compare the patterns of the equations for the two algebras. Relying on the equations, we propose a view maintenance algorithm to maintain views when they are defined with multiple operators.