On conjunctive queries containing inequalities
Journal of the ACM (JACM)
Constraint checking with partial information
PODS '94 Proceedings of the thirteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Answering queries using views (extended abstract)
PODS '95 Proceedings of the fourteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Deciding containment for queries with complex objects (extended abstract)
PODS '97 Proceedings of the sixteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Query containment for conjunctive queries with regular expressions
PODS '98 Proceedings of the seventeenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Complexity of answering queries using materialized views
PODS '98 Proceedings of the seventeenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Equivalences Among Relational Expressions with the Union and Difference Operators
Journal of the ACM (JACM)
Principles of Database and Knowledge-Base Systems: Volume II: The New Technologies
Principles of Database and Knowledge-Base Systems: Volume II: The New Technologies
IEEE Transactions on Knowledge and Data Engineering
Information Integration Using Logical Views
ICDT '97 Proceedings of the 6th International Conference on Database Theory
Queries Independent of Updates
VLDB '93 Proceedings of the 19th International Conference on Very Large Data Bases
Answering queries using views: A survey
The VLDB Journal — The International Journal on Very Large Data Bases
Optimal implementation of conjunctive queries in relational data bases
STOC '77 Proceedings of the ninth annual ACM symposium on Theory of computing
On Containment of Conjunctive Queries with Negation
ADBIS '09 Proceedings of the 13th East European Conference on Advances in Databases and Information Systems
The impact of virtual views on containment
Proceedings of the VLDB Endowment
On the containment problem for queries in conjunctive form with negation
PSI'09 Proceedings of the 7th international Andrei Ershov Memorial conference on Perspectives of Systems Informatics
Efficient reasoning in proper knowledge bases with unknown individuals
IJCAI'11 Proceedings of the Twenty-Second international joint conference on Artificial Intelligence - Volume Volume Two
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Testing containment of conjunctive queries is the question whether for any such queries Q1, Q2, for any database instance D, the set of answers of one query is contained in the set of answers of the other. In this paper, we first introduce into the general approach for testing for the case, when both queries do not contain negation. Based on these techniques we discuss the question for the case of queries with negation. We propose a new method and compare with the currently known approach. Instead of always testing the exponential number of possible canonical databases, our algorithm will terminate once a certain canonical database is constructed. However, in the worst case, still an exponential number of canonical databases has to be checked.