A. Heuer and J. Kroger. Query optimization in the CROQUE project. In Proc. 7th Int. Conf. on Database and Expert Systems Applications,volume 1134 of LNiCS, pages 489--499, Zurich, 1996.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....PCTE is an extremely efficient operation supported by the physical structures of the OMS, these considerations are not applicable in our context. Other approaches deal with the exploitation of materialized views for query processing [3] or with a general architecture for a query optimizer for OQL [12]. Summarizing, all the aforementioned approaches do not address the aspect that regular path expressions can be inverted in order to exploit index structures defined for the destination object types of the paths. 8 Conclusion and Future Work In this paper wehave presented an approach which ....

A. Heuer and J. Kroger. Query optimization in the CROQUE project. In Proc. 7th Int. Conf. on Database and Expert Systems Applications,volume 1134 of LNiCS, pages 489--499, Zurich, 1996.

....repeatedly and to control of the manner in which a query representation is traversed. Such control is not provided with Gral rules and instead must be expressed using its meta rule language as discussed below. Still to write about: ffl Cascades [Gra95, ONK 95] in more detail) ffl CROQUE [HK96] ffl Steenhagen [SABd94] Expressing Complex Query Rewrites with Rule Groups or Modules Many systems (e.g. PHH92] BG92] FG94] MDZ93] LV91] SSJ90] provide some form of meta control language for rules that includes rule grouping and sometimes sequencing. Rule groups can be associated ....

Andreas Heuer and Joachim Krger. Query optimization in the CROQUE project. In Proceedings of the 7th International Conference on Database and Expert Systems Applications (DEXA 96), LNCS 1134, pages 489--499, Zurich, Switzerland, September 1996.

....grouping and ordering rules (for rule based optimizers) 2) use of offline pre optimization ordering instead of dynamic ordering during the optimization process, 3) taking into consideration more than one ( n best ) alternatives for further evaluation. 1 Motivation The CROQUE project 1 [4, 2] is concerned with different aspects of optimization and evaluation of object oriented queries. Starting point of all our considerations are queries in ODMG s OQL ( 1] formalized in [6] that are first represented internally employing a hybrid approach of calculus and algebra [3] before being ....

A. Heuer and J. Kroger. Query Optimization in the CROQUE Project. In Proc. of the 7th Int. Conference on Database and Expert Systems Applications (DEXA `96), Zurich, Switzerland, LNCS 1134, Springer, pages 489--499, September 1996.

....to our efforts as well. Since the pure normalization approach turned out to be questionable, new (heuristic) rewrite rules for comprehensions are being developed. When and how exactly the step from the caclulus based to the algebraic query should be done, is an open problem. The recent work of [HK96], Ste95] and several others on rule based query optimizing already proved to provide valuable input to these questions. A prototype of an OQL query translator and rewriter is already operational, employing the sophisticated pattern matching facilities of the functional programming language SML. ....

Andreas Heuer and Joachim Kröger. Query optimization in the CROQUE project. Submitted for publication, March 1996.

....a discussion of their methods and the inherent drawbacks, as well as a classification represented in a tabular fashion are given in Section 3. We started our research investigating query optimization by algebraic rewriting in an object oriented framework. This was done in the CROQUE 1 [HK96, GGMS97] project where OQL ( Cat96] formalized in [RS97] queries are optimized through rewriting among other methods. But we think that the ordering of rules is a much more general problem, that should be of interest in the framework of relational (rule based) query optimization, too. ....

A. Heuer and J. Kroger. Query Optimization in the CROQUE Project. In Proc. of the 7th Int. Conference on Database and Expert Systems Applications (DEXA `96), Zurich, Switzerland, LNCS 1134, Springer, pages 489--499, September 1996.

....any random based search strategy or can be used stand alone. It may be integrated seamlessly into most of the present query optimizers without almost any effort. Keywords: Query optimization, rule based query rewriting, search strategies, heuristics 1 Introduction The CROQUE project 1 [HK96, SGG 97] is concerned with different aspects of the optimization and evaluation of object oriented queries. Starting points of all our considerations are queries in ODMG s OQL ( Cat96] formalized in [RS97] that are first represented internally in a hybrid approach of calculus and algebra ....

A. Heuer and J. Kroger. Query Optimization in the CROQUE Project. In Proc. of the 7th Int. Conference on Database and Expert Systems Applications (DEXA `96), Zurich, Switzerland, LNCS 1134, Springer, pages 489--499, September 1996.

....demonstrated by examples executed in the CROQUE prototype. The proposed heuristics can support any random based search strategy or can be used stand alone. It may be integrated seamlessly into most of the present query optimizers without almost any effort. 1 Introduction The CROQUE project 1 [8] is concerned with different aspects of the optimization and evaluation of object oriented queries. Starting points of all our considerations are queries in ODMG s OQL ( 1] formalized in [22] that are first represented internally in a hybrid approach of calculus and algebra [5] before being ....

A. Heuer and J. Kroger. Query Optimization in the CROQUE Project. In Proc. of the 7th Int. Conference on Database and Expert Systems Applications (DEXA `96), Zurich, Switzerland, LNCS 1134, Springer, pages 489--499, September 1996.

....(3) taking into consideration more than one ( n best ) alternatives for further evaluation. Keywords: Query evaluation, query optimization, rule based optimization, heuristics, transformation rules, rule classes, rule ordering. 1 Motivation: rule based optimization The CROQUE project 1 [HK96, SGG 97] is concerned with different aspects of optimization and evaluation of object oriented queries. Starting point of all our considerations are queries in ODMG s OQL ( Cat96] formalized in [RS97] that are first represented internally employing a hybrid approach of calculus and ....

A. Heuer and J. Kroger. Query Optimization in the CROQUE Project. In Proc. of the 7th Int. Conference on Database and Expert Systems Applications (DEXA `96), Zurich, Switzerland, LNCS 1134, Springer, pages 489--499, September 1996.

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