Partial Updates in Complex-Value Databases

Partial updates arise when a location bound to a complex value is updated in parallel. Compatibility of such partial updates to disjoint locations can be assured by applying applicative algebras. However, due to the arbitrary nesting of type constructors, locations of complex-value database are often defined at multiple abstraction levels and thereby non-disjoint. Thus, applicative algebras is not as smooth as its simple definition suggests. In this paper, we investigate this problem in the context of complex-value databases, where partial updates arise naturally in database transformations. We show that a more efficient solution can be obtained when generalising the notion of location and thus permitting dependencies between locations. On these grounds we develop a systematic approach to consistency checking for update sets that involve partial updates.