H.V. Jagadish, R. Agrawal, and L. Ness. "A Study of Transitive Closure As a Recursion Mechanism". In Proc. of SIGMOD Intl Conference on Management of Data. ACM, 1987.  Home/Search   Document Not in Database   Summary   Related Articles   Check

.... since most of the recursion problems occurring in real world applications are of this type [HQC88, LMR87] Furthermore, some large classes of recursive queries, e.g. linear and nonlinear recursive queries, can be translated into a TC problem proceeded and followed by relational algebra operations [JAN87, ZY87, IW88]. In this paper, we give the reader an introduction to the TC problem. Section 2 discusses some issues that are important criteria for developing algorithms to evaluate the TC of a relation. Section 3 presents an algorithm according to in: Proc. 2nd Symposium on Mathematical Fundamentals of ....

Jagadish, H., Agvawal, R., Ness, L.: A Study of Transitive Closure as a Recursion Mechanism, in: Proc. of ACM SIGMOD 1987 Annual Conference, San Francisco, May 1987, pp. 331-344.

....pervasive data modeling tools. Storing and manipulating large graphs on secondary storage can be useful in graph oriented data management systems, such as G [1] hypertext systems like HAM [2, 3] or at the object storage level of objectoriented database systems. Several authors have pointed out [4, 5, 6] that most of the recursive queries that appear in practice can be viewed as graph traversals. When graphs are large, simply loading them completely into main memory (or virtual memory) and applying standard main memory algorithms may not be practical or desirable. For example, suppose a ....

H. V. Jagadish, Rakesh Agrawal, and Linda Ness. A study of transitive closure as a recursion mechanism. In Proceedings of ACM-SIGMOD 1987, pages 331--344. ACM Press, 1987.

....computation. Traditional research in database query languages [1] transitive closure [6] and recursive query processing [13] has approached single pair path computation as a special case of more general problems. For example, partial transitive closure computation [8] and transitive closures [7] have been used for single pair path computations. Previous evaluation of the transitive closure algorithms examined the iterative, logarithmic, Warren s, Depth first search (DFS) hybrid, and spanning tree based algorithms [14] Previous evaluation of single pair path computation algorithms in a ....

H.V. Jagadish, R. Agrawal, and L. Ness. "A Study of Transitive Closure As a Recursion Mechanism". In Proc. of SIGMOD Intl. Conference on Management of Data. ACM, 1987.

.... of database logic programs, but who are familiar with relational algebra (or relational calculus) For example, in [Agr87] an operator is proposed that makes it possible for a certain class of recursive queries to be expressed (basically transitive closure plus some aggregative queries) In [JAN87] the link between transitive closure queries and linear Datalog is better clarified by showing that every linear recursive query can be expressed as a transitive closure query possibly preceded and followed by operations already available in relational algebra. This important result is obtained by ....

H. V. Jagadish, Rakesh Agrawal, and Linda Ness. A Study of Transitive Closure as a Recursion Mechanism. In , pages 331--344, 1987.

....level. Using such an order OBOM computes BOM in only one call to CJOIN , as we shall show. 1. 1 Related Work A transitive closure operator for database queries was first proposed by Zloof in [Zloo75] Since then it has been shown that linear recursive queries can be expressed by such an operator [JaAN87, ChHa82], and an extension of relational algebra that includes a transitive closure operator called ff algebra has been proposed in [Agra87] Furthermore, Agrawal [Agra87] as well as many others) proposed that specialized algorithms that exploit the knowledge of the physical database can be built into ....

Jagadish, H. V., Agrawal, R., Ness, L., "A Study of Transitive Closure as a Recursion Mechanism," Proc. ACM-SIGMOD 1987 Int'l Conf. on Management of Data, May 1987.

.... [Codd70, Codd72] are limited in their expressive power especially in expressing recursive queries [Ullm88a] A transitive closure operator for database queries was first proposed by Zloof in [Zloo75] Since then it has been shown that linear recursive queries can be expressed by such an operator [JaAN87, ChHa82], and an extension of relational algebra that includes a transitive closure operator called ff algebra has been proposed in [Agra87] Furthermore, Agrawal (as well as many others) proposed that specialized algorithms that exploit the knowledge of the physical database can be built into the ....

Jagadish, H. V., Agrawal, R., Ness, L., "A Study of Transitive Closure as a Recursion Mechanism," Proc. ACM-SIGMOD 1987 Int'l Conf. on Management of Data, May 1987.

....problem is approached from two different perspectives: algebraic optimization and logic optimization. This is not surprising, since the semantics of Datalog programs (that is, pure Horn clauses without function symbols) can be expressed as Relational Algebra equations under a fixpoint semantics [33, 37]. This ensures the applicability of bottom up evaluation and optimization methods to both recursive algebraic expressions and logic rules. Examples of research on algebraic optimization may be found in [5, 7, 10, 13, 16, 26, 37] examples of logic optimization may be found in [11, 12, 39, 41, 42, ....

H.V. JAGADISH, R. AGRAWAL, AND L. NESS, "A study of transitive closure as a recursion mechanism" in Proc. ACM-SIGMOD Conf., 1987, pp. 331-344.

.... [27] 28] and in the context of parallel database machines, such as PRISMA [6] 21] The main goal is, of course, to speed up processing by the use of more resources (processors) Recently, transitive closure queries have become more and more important: a body of research has been performed [1, 3, 19, 20, 24, 26], and transitive closure is being supported by some database systems [10] The transitive closure of a relation R is defined as S n i=1 R i (which is equal to R [ R 1 R) R 1 (R 1 R) Over the past decade we see a trend towards distributed computation of queries. First ....

Jagadish, H.V., Agrawal, R. and Ness, L. `A study of transitive closure as a recursion mechanism,' in Proc. Int. Conf. on Management of Data, ACM-SIGMOD, 1987. pp. 331--344.

....may be even more computationally expensive than join operations. Much research has been published on the subjects of (a) exploiting parallel computing in query processing, e.g. in [KM91] AJ88] VK88b] and (b) techniques and operators for recursive query processing, e.g. in [Agr87] IW91] [JAN87], Nau87] NRSU89] Sag88] VB86] VK88a] YKLH92] and many others. Furthermore some research has also examined the application of parallel computing to recursive query processing [CW89] In order to bring this work into the mainstream of commercial DBMS query processing, it is necessary to ....

....to be obtained from observing the performance of the algorithmic technique on the target parallel computer. We illustrate this process in the case of linear recursive queries. After some outlining comments about linear recursion probably the most common class of recursion in queries [BR86] [JAN87] [YKLH92] section 2 concludes with an example of a linear recursive query which is sufficiently general to show the relevant computational properties of two processing techniques, namely ffl bottom up evaluation (section 3) and ffl transitive closure evaluation (section 4) The transitive ....

[Article contains additional citation context not shown here]

H.V. Jagadish, R. Agrawal, and L. Ness. A Study of Transitive Closure As a Recursion Mechanism. In Proceedings ACM SIGMOD 1987 Conference on Management of Data, pages 331--344, 1987.

.... of database logic programs, but who are familiar with relational algebra (or relational calculus) For example, in [Agr87] an operator is proposed that makes it possible for a certain class of recursive queries to be expressed (basically transitive closure plus some aggregative queries) In [JAN87] the link between transitive closure queries and linear Datalog is better clarified by showing that every linear recursive query can be expressed as a transitive closure query possibly preceded and followed by operations already available in relational algebra. This important result is obtained by ....

H. V. Jagadish, Rakesh Agrawal, and Linda Ness. A Study of Transitive Closure as a Recursion Mechanism. In ACM-SIGMOD Intl. Conf. on Management of Data, pages 331--344, 1987.

.... by a transitive closure algorithm [10] and a multi chain recursion by magic sets or counting [1, 2] One may have wondered whether queries on multi chain recursions can be evaluated efficiently by merging multiple chain generating paths into one and then applying transitive closure algorithms [11]. However, since such multiple paths do not share variables, the merge of them implies iterative processing on the cross product(s) of several relations, each corresponding to a path. It is terribly inefficient to perform iterative evaluation on the cross product of two or more database relations ....

H. V. Jagadish, R. Agrawal, and L. Ness. A study of transitive closure as a recursion mechanism. In Proc. 1987 ACM-SIGMOD Int. Conf. Management of Data, pages 331--344, San Francisco, CA, May 1987.

....and the Dijkstra 0 s algorithm, that traverses the graph based on priorities [6] work better in main memory environments. Recently proposed transitive closure algorithms [2, 3, 12, 13] provide disk based solutions that can be adopted to solve linear recursive queries in relational databases [14]. Among these, Ioannidis et al. s Path BTC algorithm is based on depth first graph traversal [13] Agrawal et al. s hybrid algorithms is a combination of matrix based and graph traversal approaches [2, 3] The Path BTC and hybrid algorithms are similar in that both use Tarjan s algorithm [20] as ....

Jagadish, H. V. and Agrawal, R., "A Study of Transitive Closure as a Recursion Mechanism," Proc. ACMSIGMOD, May 1987, pp. 331 -- 344.

.... ) q(Y 2 ; Y 1 ) q(Y 1 ; Z) The union of the sequences of q literals is the transitive closure Q of Q so P (X; Z) Q (X; Z) Jagadish et al. show that every linear recursive Datalog query can be evaluated by using a suitable transitive closure algorithm to eliminate recursion (see [Jag 87] This can be done by analysing the substitution graph of the linear recursive rule. This technique forms the basis of the implementation described in subsequent chapters of this report. An important point regarding the approach of [Jag 87] is that linear recursion cannot be effectively replaced ....

....transitive closure algorithm to eliminate recursion (see [Jag 87] This can be done by analysing the substitution graph of the linear recursive rule. This technique forms the basis of the implementation described in subsequent chapters of this report. An important point regarding the approach of [Jag 87] is that linear recursion cannot be effectively replaced by a data independent number (i.e. a number that can be derived from the rules) of transitive closure operations. This can be seen by the following example. Example 5: The linear recursive query p(X; Z) Gamma e(X; Z) Exit Rule p(X; ....

[Article contains additional citation context not shown here]

H. V. Jagadish, R. Agrawal, L. Ness, A Study of Transitive Closure As a Recursion Mechanism, Proc. ACM SIGMOD 1987 Conference on Management of Data, pp. 331344

....this family of algorithms can be generalized to solve path problems and to solve problems in which some selection criteria have been specified for source or destination nodes. 1. INTRODUCTION Transitive closure is regarded to be an important operation for the next generation of database systems [1, 5, 6, 12, 13, 15, 17, 19, 21], and considerable research has been devoted to designing algorithms for computing the transitive closure of database relations [2, 4, 9 11, 16, 24] These algorithms can be classified into three major families. Iterative algorithms, such as semi naive [4] logarithmic [10, 24] and variations ....

H. V. Jagadish, R. Agrawal, and L. Ness, "A Study of Transitive Closure as a Recursion Mechanism," Proc. ACMSIGMOD 1987 Int'l Conf. on Management of Data, San Francisco, California, May 1987, pp. 331-344.

No context found.

H.V. Jagadish, R. Agrawal, and L. Ness. "A Study of Transitive Closure As a Recursion Mechanism". In Proc. of SIGMOD Intl Conference on Management of Data. ACM, 1987.

No context found.

H.V. Jagadish, R. Agrawal, & L. Ness "A Study of Transitive Closure as a Recursion mechanism" SIGMOD Record 16,#3, December 1987, pp 331-344.

No context found.

H.V. Jagadish, R. Agrawal, and L. Ness, A study of transitive closure as a recursion mechanism. Proc. ACM-SIGMOD Conf., May 1987.

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