Updating XML Views: The Clean Source Theory

XML has become a primary data model to wrap heterogeneous data sources using views. However, as is commonly known, views and thus also such XML views suffer from the view update problem. In this paper, we characterize the search space of all potential correct update mappings in the context of the source data also being XML. This is achieved by proposing the notion of a source and of a clean source for a given XML view element. Further, we introduce the clean source theory to determine whether a given view update mapping is correct. This now serves as a solid theoretical foundation for developing practical algorithms towards update translatability checking. We also provide a concrete case study that applies this theory to assess the translatability of XML view updates with different update types.