C. Beeri and R. Ramakrishnan. On the power of magic. In Proceedings of the Sixth ACM Symposium on Principles of Database Systems, pages 269--293, San Diego, CA, March 1987. 32  Home/Search   Document Details and Download   Summary   Related Articles   Check

.... n) is the empty chain then return TRUE [1] goal G#leftmost literal in [2] R A literals of potentially unifiable with complement of (for reductions) 3] E input clauses with literals potentially unifiable with complement of (for extensions) try to solve [4] for each l R inRdo resources available if reduction made 0 and l R and complement of [7] if Solve(reduce(C, l R ,#) n new ) then [8] return TRUE endfor (reduction) 9] for each clause C in E with literal l C do resources available if extension of with C is made 0 and and l ....

....requires the identification of useful lemmas which is a di#cult task itself. 8 Related Work Much work has been done in the area of query optimization for deductive databases [3] This work tends to focus on reducing redundant (recursive) derivations by program transformation techniques [4], by introducing a control language [15, 16] and by run time analysis [38] In general, these techniques are designed to work with function free, Horn (Datalog) programs. As our results with SAM s lemma indicate, caching and heuristic caching can work well for this class of problem. The framework ....

C. Beeri and R. Ramakrishnan. On the power of magic. In Proceedings of the 6th Symposium on Principles of Database Systems, pages 269--283, 1987.

....in combination with the concept weak stratification, however, may lead to a set of answers which is neither sound nor complete with respect to the well founded model. This problem is cured by introducing the new concept soft stratification instead. 1. INTRODUCTION The Magic Sets rewriting [3, 5] technique for query evaluation seems to be the most promising approach to evaluating database queries for database systems with a powerful view concept. This is in particular the case for systems which will implement the new SQL:1999 standard, and hence will allow the definition of recursive ....

....The wellfounded model is then given by F # p(1, 1) p(1, 2) p(1, 3) p(2, 1) p(2, 2) p(2, 3) # h(1, 3) h(2, 3) 3. MAGIC SETS Various methods for e#cient bottom up evaluation of queries against the intensional part of a database have been proposed, e.g. Magic Sets [4] Counting [5], Alexander method [16] All these approaches are rewriting techniques for deductive rules with respect to a given query such that bottom up materialization is performed in a goal directed manner cutting down the number of irrelevant facts generated. In the following we will focus on Magic Sets ....

Beeri, C., Ramakrishnan, R.: On the Power of Magic. JLP 10(1/2/3&4): 255-299 (1991).

.... has been already presented in two recent papers [3, 5] based on the use of equalities and disequalities in the line of CRWL [9] and CRWLF [16] This querying mechanism proposed a goal directed bottom up evaluation of a functional logic program based on program transformation and magic sets [6]. Here, we will state that the three proposed querying mechanisms (the presented one in [3, 5] calculus and algebra) are equivalent, that is, they will obtain the same answers. The work developed in this paper, together with the above quoted papers, provides the basis of the language INDALOG [4] ....

C. Beeri and R. Ramakrishnan. On the Power of Magic. JLP, 10(3,4):255-299, 1991.

....the entire closure of a program. More precisely, it may be possible to compute only a small and relevant subset of the closure in order to prove a given goal. Similarly, the bottom up xpoint computation can be made more ecient, by incorporating ideas similar to the well known magic sets method [3]. We are currently investigating these and other optimization opportunities. We have completed a prototype implementation [14, 15] based on translation to coral [25] and are working on a direct implementation. We are also investigating relaxations to the present restrictions on ORLog programs ....

C. Beeri and R. Ramakrishnan. On the power of magic. In Proceedings of the 6th ACM Symposium on Principles of Database Systems, pages 269-283, 1987.

....will be the large item sets. Notice that now we have to discard nodes ad 0 and d 2 too. This raises the question, is it possible to utilize the support and con dence thresholds provided in the query and prune candidates for intersection any further. Ideas similar to magic sets transformation [3, 24] may be borrowed to address this issue. The only problem is that pruning of any node depends on its support count which may come at a later stage. By then all nodes may already have been computed and thus pushing selection conditions inside aggregate operator may become non trivial. Special data ....

C. Beeri and R. Ramakrishnan. On the power of magic. In Proceedings of the 6th ACM Symposium on Principles of Database Systems, pages 269-283, 1987.

....a matching conclusion literal. Thus, it is very easy to formulate parameterized versions of a query just by replacing one or more variables by a constant. Implementation techniques for query optimization have been thoroughly investigated yielding algorithms for recursion optimization (magic sets [8], query subquery approach [42] and deductive integrity enforcement (e.g. 3] 35] View maintenance algorithms (storing the result of a query and keeping it up to date with the database) have been less studied but are rather simple generalizations of integrity enforcement. Some work has been ....

....to the instances of the concerned attribute classes. This technique can be extended to views containing complex objects as well [27] The rule view of queries allows the application of the standard deductive optimization techniques. One example is the application of the magic set rewriting method [8] to the rules generated from query classes. A bottom up fixpoint procedure using the rewritten rules only computes information that is relevant to a given query. From the concept view of queries the search space restriction for query evaluation by placing query classes in the object base using ....

C. Beeri and R. Ramakrishnan, "On the power of magic", in Proc. 6th ACM SIGMOD-SIGACT Symp. on Principles of Database Systems, 1987.

....:IE 1 (e) IE 1 (e) Gamma A:#boss(e; m) The last Datalog rule is an auxiliary rule concluding a new literal IE 1 . It results from resolving the negated existential quantification. Among the standard deductive optimization techniques, we chose the supplementary magic set rewriting method ([BR87]) because of its closeness to the idea of parameterized query classes. An application of a bottom up fixpoint procedure for evaluation purposes to magic rule sets guarantees to make only intensional information explicit which is relevant for a given query. The magic set rewriting always takes ....

Beeri C., Ramakrishnan R., "On the power of magic", In Proc. 6th ACM SIGMOD-SIGACT Symp. on Principles of Database Systems.

....bindings are allowed by a source. In this article we use bound free adornments to describe relation restrictions. As we will see in Section 7, without executing a plan, we do not know whether the tuples for the nonanswerable subgoals can join with all the tuples in the supplementary relations [BR87] of the answerable subgoals. Thus the computability of the complete answer is data dependent. 2 Problem Formulation In this section, we formalize the problem studied in this article. We use binding patterns of relations to model their limited access patterns [Ull89] A binding pattern of a ....

....for its stability. Lemma 3.1 A feasible CQ is stable. # Proof: Let a feasible CQ Q have a feasible order g 1 ( X n ) of all its subgoals. For any database D, we can compute ANS(Q,D) by executing the following linear plan. Compute the corresponding sequence of n supplementary relations [BR87, Ull89] I 1 , I n , where I i is the supplementary relation after the first i subgoals have been processed. Return the supplementary relation I n . Now we prove this linear plan computes ANS(Q,D) For each tuple t ANS(Q,D) suppose that t comes from the tuples t 1 , t n of the ....

Catriel Beeri and Raghu Ramakrishnan. On the power of magic. In PODS, pages 269-- 283, 1987. 94] Sudarshan S. Chawathe et al. The TSIMMIS project: Integration of heterogeneous information sources. IPSJ, pages 7--18, 1994.

....counting rule of Fig. 7(b) This can, for instance, be accomplished by redefining the goal x x of Fig. 7(b) x x : assert(cnt. 2(0, x, x0) 2(0) This is a rather coarse solution, presented here only as a quick illustration on how things could function; a more refined solution is given in [8]. Trivial modified rules It is easy to see that the only function of the modified recurslye rule in Fig. 9, is to decrement the index to zero one step at a time. We can thus dispense with this rule and write a new modified goal: cnt. t : x,s(x) 214 D. accd, C . Zaniolo G: C1 C27 ....

....to arbitrary recurslye predicates, including those featuring mutual recursion and nonlinear recursion. The paper also discussed the application of the method to solve nested recursire predicates (a further extension of the Generalized Counting Method for handling such kind of queries is given in [8]) A sufficient condition for the finiteness of the fixpoint computations was finally given; although quite simple, this condition seems adequate for many common cases involving recursi ve predicates with function symbols. It thus appears that the Generalized Counting Method provides a very ....

C. lleeri and R. Ramakrishnan, On the power of magic, in: Proc. ACM SIGMOD-SIGACT&'m. on Principles of Database Systems (1987) 269-283.

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C. Beeri and R. Ramakrishnan. On the Power of Magic. In PODS, 1987.

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C. Beeri and R. Ramakrishnan. On the power of magic. In Proceedings of the Sixth ACM Symposium on Principles of Database Systems, pages 269--293, San Diego, CA, March 1987. 32

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Beeri, C. and Ramakrishnan, R., "On the power of magic," pp. 269-293 in Proceedings of the Sixth ACM Symposium on Principles of Database Systems, (San Diego, CA, March 1987), (March 1987).

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Beeri, C. and Ramakrishnan, R., "On the power of magic," pp. 269-293 in Proc. of the Sixth ACM Symp. on Princ. of Database Syst., (San Diego, CA, Mar. 1987), (1987).

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C. Beeri and R. Ramakrishnan. On the Power of Magic. In PODS, 1987.

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C. Beeri and R. Ramakrishnan. On the Power of Magic. In Sixth ACM Symposium on Principles of Database Systems, pages 269--284, 1987.

No context found.

C. Beeri and R. Ramakrishnan. On the power of magic. J. Log. Program, 10, 1991.

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C. Beeri and R. Ramakrishnan. On the Power of Magic. In Sixth ACM Symposium on Principles of Database Systems, pages 269-- 284, 1987.

No context found.

C. Beeri and R. Ramakrishnan. On the Power of Magic. In Sixth ACM Symposium on Principles of Database Systems, pages 269--284, 1987.

No context found.

C. Beeri and R. Ramakrishnan. On the Power of Magic. In PODS, 1987.

No context found.

C. Beeri and R. Ramakrishnan. On the power of magic. In Proceedings of the Sixth ACM Symposium on Principles of Database Systems, pages 269--293, San Diego, CA, March 1987.

No context found.

C. Beeri and R. Ramakrishnan. On the Power of Magic. In Sixth ACM Symposium on Principles of Database Systems, pages 269-- 284, 1987.

No context found.

C. Beeri and R. Ramakrishnan. On the Power of Magic. In Sixth ACM Symposium on Principles of Database Systems, pages 269--284, 1987.

No context found.

C. Beeri and R. Ramakrishnan. On the Power of Magic. In Sixth ACM Symposium on Principles of Database Systems, pages 269--284, 1987.

No context found.

Catriel Beeri and Raghu Ramakrishnan. On the power of magic. In Proceedings of the Sixth ACM Symposium on Principles of Database Systems, pages 269--283, 1987.

No context found.

C. Beeri and R. Ramakrishnan. On the Power of Magic. In Sixth ACM Symposium on Principles of Database Systems, pages 269--284, 1987.

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