Magic sets and other strange ways to implement logic programs (extended abstract)
PODS '86 Proceedings of the fifth ACM SIGACT-SIGMOD symposium on Principles of database systems
Efficient evaluation of right-, left-, and multi-linear rules
SIGMOD '89 Proceedings of the 1989 ACM SIGMOD international conference on Management of data
Right-, left-, and multi-linear rule transformations that maintain context information
Proceedings of the sixteenth international conference on Very large databases
SIGMOD '90 Proceedings of the 1990 ACM SIGMOD international conference on Management of data
Magic templates: a spellbinding approach to logic programs
Journal of Logic Programming
Magic-sets transformation in nonrecursive systems
PODS '92 Proceedings of the eleventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Bottom-up evaluation and query optimization of well-founded models
Theoretical Computer Science
Argument reduction by factoring
Theoretical Computer Science
Magic factoring of closure programs (extended abstract)
PODS '95 Proceedings of the fourteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Optimizing existential datalog queries
Proceedings of the seventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Soft stratification for magic set based query evaluation in deductive databases
Proceedings of the twenty-second ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
| Hi-index | 0.00 |
We reconsider query evaluation in stratifiable deductive databases using Magic Sets. On the basis of the soft stratification approach, a new solution to the problem of optimizing existential queries in a set-oriented database language like Datalog is presented. To this end, the query answering process is optimized in such a way that after the generation of one appropriate answer fact with respect to a (derived) existential query, the redundant computations of alternative answer facts are avoided. The same technique can be employed for avoiding the generation of subsumed answers and sub-queries as well. It is shown that in presence of recursion or stratified negation this may considerably reduce the total number of facts generated.