Views in a Large Scale XML Repository
Résumé
We are interested in defining and querying views in a huge and highly heterogeneous XML repository (Web
scale). In this context, view definitions are very large, involving lots of sources, and there is no apparent
limitation to their size. This raises interesting problems that we address in the paper: (i) how to distribute
views over several machines without having a negative impact on the query translation process; (ii) how to
quickly select the relevant part of a view given a query; (iii) how to minimize the cost of communicating
potentially large queries to the machines where they will be evaluated. The solution that we propose is based
on a simple view definition language that allows for automatic generation of views. The language maps paths
in the view abstract DTD to paths in the concrete source DTDs. It enables a distributed implementation of
the view system that is scalable both in terms of data and load. In particular, the query translation algorithm
is shown to have a good (linear) complexity.