We show that excellent performance can be delivered by materializing a reasonable number of views and we provide an algorithm that selects a number of views to precompute and materialize given specific space constraints. In WWW 10, 2001. XQForms inputs an XML schema and a declarative specification of query forms and result pages and produces a Web front-end that interacts with the user, emits XMAS queries to an underlying XML data server and formats the results in real time. We present the Sesame system for the efficient modeling and execution of what-if scenarios. We model what-if scenarios as a list of hypothetical modifications on the warehouse view and fact data.
Execution is based on substitution and rewriting.
The rewriting module uses axiomatic knowledge of the arithmetic, relational, and financial to efficiently rewrite the query. Special rewriting challenges arise from the size and nature of the queries derived by the substitution module and because of the wide variety of operators in the views and query. The blending part of it comes in when one uses the result of a query as the source upon which the next query is posed. The ICDE 99 paper had proposed the soundness and tightness concepts for measuring the descriptive ability of DTDs. This paper shows some strong inherent limitations on the descriptive power of DTDs.