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