Applying an update method to a set of receivers

In the context of object databases, we study the application of an update method to a collection of receivers rather than to a single one. The obvious strategy of applying the update to the receivers one after the other, in some arbitrary order, brings up the problem of order independence. On a very general level, we investigate how update behavior can be analyzed in terms of certain schema annotations, called colorings. We are able to characterize those colorings that always describe order-independedent updates. We also consider a more specific model of update methods implemented in the relational algebra. Order-independence of such algebraic methods is undecidable in general, but decidable if the expressions used are positive. Finally, we consider an alternative parallel strategy for set-oriented applications of algebraic update methods and compare and relate it to the sequential strategy.</jats:p

Applying an Update Method to a Set of Receivers (Extended Abstract)

In the context of object databases, we study the application of an update method to a collection of receivers rather than to a single one. The obvious strategy of applying the update to the receivers one after the other, in some arbitrary order, brings up the problem of order independence. On a very general level, we investigate how update behavior can be analyzed in terms of certain schema annotations called colorings. We are able to characterize those colorings which always describe order-independent updates. We also consider a more specific model of update methods implemented in the relational algebra. Order independence of such algebraic methods is undecidable in general, but decidable if the expressions used are positive. Finally, we consider an alternative parallel strategy for set-oriented application of algebraic methods and compare and relate it to the sequential strategy. 1 Introduction In object systems, update procedures are provided by methods, which are applied to a rec..