Translating OQL into Monoid Comprehensions : Stuck with Nested Loops?


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GRUST, Torsten, Marc H. SCHOLL, 1996. Translating OQL into Monoid Comprehensions : Stuck with Nested Loops?

@techreport{Grust1996Trans-6407, series={Konstanzer Schriften in Mathematik und Informatik}, title={Translating OQL into Monoid Comprehensions : Stuck with Nested Loops?}, year={1996}, number={3}, author={Grust, Torsten and Scholl, Marc H.} }

Translating OQL into Monoid Comprehensions : Stuck with Nested Loops? 2011-03-24T16:12:29Z This work tries to employ the monoid comprehension calculus - which has proven to be an adequate framework to capture the semantics of modern object query languages featuring a family of collection types like sets, bags, and lists - in a twofold manner: First, serving as a target language for the translation of ODMG OQL queries. We review work done in this field and also give comprehension calculus equivalents for the recently introduced OQL 1.2 concepts.<br /><br />Second, we use monoid comprehensions as the formalism in which we try to find efficient execution methods working on a rich set of physical structures (including indices, vertical and horizontal decomposition, etc.). The main problem coming up here is the "nested-loop nature" of the calculus expressions. While these loop-based semantics for evaluating comprehensions at least provide a way for executing OQL queries, their execution is almost always much less efficient than alternative physical algorithms of the database engine (e.g. different types of joins).<br /><br />We are able to capture these efficient algorithms in the comprehension formalism, too. Furthermore, comprehensions are amenable to pattern-matching driven rewriting. This paper studies query rewrite optimization using monoid comprehensions and shows that efficient implementation plans can be derived in this framework. eng terms-of-use Grust, Torsten Scholl, Marc H. 2011-03-24T16:12:29Z Scholl, Marc H. Grust, Torsten application/pdf 1996

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