An Algebraic Approach to the Complexity of Generalized Conjunctive Queries.
Michael BaulandPhilippe ChapdelaineNadia CreignouMiki HermannHeribert VollmerPublished in: SAT (Selected Papers (2004)
Keyphrases
- conjunctive queries
- conjunctive query containment
- query answering
- combined complexity
- data complexity
- integrity constraints
- query evaluation
- conjunctive regular path queries
- np complete
- conp complete
- data exchange
- special case
- bounded treewidth
- query rewriting
- query language
- probabilistic databases
- decision procedures
- lower complexity
- hypertree decomposition
- unions of conjunctive queries
- query containment
- fixed parameter tractable
- databases
- queries using views
- pspace complete
- data sets
- computational complexity
- deductive databases
- query complexity
- expressive power
- xml data
- boolean expressions
- schema mappings
- containment of conjunctive queries
- relational queries
- datalog programs