Optimization of nested SQL queries revisited
SIGMOD '87 Proceedings of the 1987 ACM SIGMOD international conference on Management of data
Towards an efficient evaluation of general queries: quantifier and disjunction processing revisited
SIGMOD '89 Proceedings of the 1989 ACM SIGMOD international conference on Management of data
Query evaluation techniques for large databases
ACM Computing Surveys (CSUR)
On optimizing an SQL-like nested query
ACM Transactions on Database Systems (TODS)
Query Optimization in Database Systems
ACM Computing Surveys (CSUR)
Orthogonal optimization of subqueries and aggregation
SIGMOD '01 Proceedings of the 2001 ACM SIGMOD international conference on Management of data
ToXgene: a template-based data generator for XML
Proceedings of the 2002 ACM SIGMOD international conference on Management of data
Optimization and Evaluation of Disjunctive Queries
IEEE Transactions on Knowledge and Data Engineering
ICDE '96 Proceedings of the Twelfth International Conference on Data Engineering
VLDB '87 Proceedings of the 13th International Conference on Very Large Data Bases
Yet Another Query Algebra For XML Data
IDEAS '02 Proceedings of the 2002 International Symposium on Database Engineering & Applications
DBPL '01 Revised Papers from the 8th International Workshop on Database Programming Languages
Anatomy of a native XML base management system
The VLDB Journal — The International Journal on Very Large Data Bases
Nested Queries and Quantifiers in an Ordered Context
ICDE '04 Proceedings of the 20th International Conference on Data Engineering
Full-Fledged Algebraic XPath Processing in Natix
ICDE '05 Proceedings of the 21st International Conference on Data Engineering
A Complete and Efficient Algebraic Compiler for XQuery
ICDE '06 Proceedings of the 22nd International Conference on Data Engineering
Algebraic Optimization of Nested XPath Expressions
ICDE '06 Proceedings of the 22nd International Conference on Data Engineering
Hi-index | 0.00 |
XML query languages feature powerful primitives for formulating queries, involving comparison expressions which are existentially quantified. If such comparisons involve several scopes, they are correlated and, thus, become difficult to evaluate efficiently. In this paper, we develop a new ternary operator, called Kappa-Join, for efficiently evaluating queries with existential quantification. In XML queries, a correlation predicate can occur conjunctively and disjunctively. Our decorrelation approach not only improves performance in the conjunctive case, but also allows decorrelation of the disjunctive case. The latter is not possible with any known technique. In an experimental evaluation, we compare the query execution times of the Kappa-Join with existing XPath evaluation techniques to demonstrate the effectiveness of our new operator.