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MARS |
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A System for Publishing XML from 'Mixed and Redundant Storage'
| Welcome to the MARS Website! MARS was created as a a system for publishing XML from Mixed and Redundant Storage. The core of the system is a universal tool for query reformulation and optimization under constraints, given an (equivalent) relational model. | |
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What MARS is a system for publishing as XML data from mixed, relational+XML, proprietary storage, while supporting redundancy in storage for tuning purposes. The correspondence between public and proprietary schemas is given by a combination of LAV and GAV-style views expressed in XQuery. XML and relational integrity constraints are also taken into consideration. Starting with client XQueries formulated against the public schema, MARS achieves the combined effect of rewriting-with-views, composition-with-views and query minimization under integrity constraints to obtain optimal reformulations against the proprietary schema. |
Why The problem of query reformulation is a very general one: given two schemas P and S and a correspondence CR between them, and given a query Q formulated in terms of P, find a query X formulated in terms of S that is equivalent to Q modulo the correspondence CR. |
The Demo The demo focuses on the chase of relational queries and constraints, in which the only logical connector allowed is the conjunction. Nevertheless, the last version of MARS supports disjunction also. The interface allows to visualize the individual steps of a chase sequence and to navigate through them, showing each time how the chosen constraint was mapped into the query and how the query was modified, leading to a new query plan. |
Acknowledgement This material is based upon work supported by the National Science Foundation under Grant No. IIS-0347968 (CAREER). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. |
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| MARS Home Page | MARS Demo |