Algebraic equivalences of nested relational operators

Liu, Hong-Cheu; Yu, Jeffery Xu

doi:10.1016/j.is.2003.12.001

Cited by 8 publications

(6 citation statements)

References 25 publications

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“…Further research on this topic includes the issues of optimization of translated algebraic expressions [20,25], safe queries in the web scenario, and the open problem of whether a broader subclass of domain independent formulas can be recognized efficiently.…”

Section: Conclusion and Further Researchmentioning

confidence: 99%

Safety, domain independence and translation of complex value database queries

Liu

Liang

2008

Information Sciences

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Section: Conclusion and Further Researchmentioning

confidence: 99%

Safety, domain independence and translation of complex value database queries

Liu

Liang

2008

Information Sciences

Self Cite

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“…However, optimization of nested relational operators is more complicated compared to relational operators. Algebraic optimization of nested relational operators have been studied [Scholl 1986;Jan 1990;Liu and Ramamohanarao 1994;Liu and Yu 2005]. Scholl [1986] presents a series of equivalence rules among algebraic expressions containing unnest and reduction operators as well as selections and projections.…”

Section: Algebraic Optimizationmentioning

confidence: 99%

“…Jan [1990] discusses the commutative properties of nested relational operators in the context of optimizations. Liu and Ramamohanarao [1994], Liu and Yu [2005] investigate some algebraic properties of their extended nested relational operators and proposed several algebraic transformation rules. They also outline an algorithm that uses those rules to transform an initial query tree into an optimized tree.…”

Section: Algebraic Optimizationmentioning

confidence: 99%

SQL query optimization through nested relational algebra

Cao

Badia

2007

ACM Trans. Database Syst.

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Most research work on optimization of nested queries focuses on aggregate subqueries. In this article, we show that existing approaches are not adequate for nonaggregate subqueries, especially for those having multiple subqueries and certain comparison operators. We then propose a new efficient approach, the nested relational approach, based on the nested relational algebra. The nested relational approach treats all subqueries in a uniform manner, being able to deal with nested queries of any type and any level. We report on experimental work that confirms that existing approaches have difficulties dealing with nonaggregate subqueries, and that the nested relational approach offers better performance. We also discuss algebraic optimization rules for further optimizing the nested relational approach and the issue of integrating it into relational database systems.

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“…Like in the algebraic paradigm, we may improve performance by exploiting relational optimisation techniques, for example, optimizing subset queries [9], index support, algebraic equivalences for nested relational operators [10]. Optimisation for data mining queries also requires novel techniques, not just extensions of object-relational optimisation technology.…”

Section: Performance and Optimisation Issuesmentioning

confidence: 99%

A Logic-Based Approach to Mining Inductive Databases

Liu

Zeleznikow

et al. 2007

Computational Science – ICCS 2007

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Abstract. In this paper, we discuss the main problems of inductive query languages and optimisation issues. We present a logic-based inductive query language and illustrate the use of aggregates and exploit a new join operator to model specific data mining tasks. We show how a fixpoint operator works for association rule mining and a clustering method. A preliminary experimental result shows that fixpoint operator outperforms SQL and Apriori methods. The results of our framework could be useful for inductive query language design in the development of inductive database systems.

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Algebraic equivalences of nested relational operators

Cited by 8 publications

References 25 publications

Safety, domain independence and translation of complex value database queries

Safety, domain independence and translation of complex value database queries

SQL query optimization through nested relational algebra

A Logic-Based Approach to Mining Inductive Databases

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