An Efficient Algorithm for XML Type Projection

In the contexts of data integration and data exchange, schema mappings are primarily used for query answering. As a consequence, their maintenance and, in particular, the detection of corrupted mappings, i.e., mappings that fail in matching the source and/or the target schema, is crucial. Corruption checking can be automatically performed by relying on an operation called type projection. This work describes an efficient algorithm for checking XML type projection, based on a characterization of type projection in terms of type simulation.