Keyphrases
- expressive power
- deductive databases
- query answering
- query language
- datalog programs
- database languages
- transitive closure
- logic programming
- integrity constraints
- ontology based data access
- relational algebra
- database
- e learning
- relational query languages
- complex objects
- dl programs
- existentially quantified
- containment of conjunctive queries
- datalog queries
- fixpoint
- data exchange
- relational databases
- expert systems
- high level
- learning algorithm