Keyphrases
- expressive power
- deductive databases
- query answering
- query language
- datalog programs
- integrity constraints
- transitive closure
- ontology based data access
- containment of conjunctive queries
- logic programming
- data complexity
- relational query languages
- data sets
- datalog queries
- relational algebra
- data exchange
- relational calculus
- database languages
- data structure
- existentially quantified
- case study
- web services
- e learning