PRATA: A system for XML publishing, integration and view maintenance

We present PRATA, a system that supports the following in a uniform framework: (a) XML publishing, i.e., converting data from databases to an X ML document, (b) XML integration, i.e., extracting data from multiple, distributed databases, and integrating the data into a single XML document, and (c) incremental maintenance of published or integrated XML data (view), i.e., in response to changes to the source databases, efficiently propagating the source changes to the XML view by computing the corresponding XML changes. A salient feature of the system is that publishing, integration and view maintenance are schema-directed: they are conducted strictly following a user-specified (possibly recursive and complex) XML schema, and guarantee that the generated or modified XML document conforms to the predefined schema. We discuss techniques underlying PRATA and report the current status of the system.