Keyphrases
- database query languages
- logic programming
- expressive power
- algebraic structure
- relational algebra
- deductive databases
- query language
- query answering
- relational query languages
- database systems
- fixpoint semantics
- type checking
- relational calculus
- formal semantics
- integrity constraints
- data model
- transitive closure
- datalog programs
- aggregate functions
- semantic information
- database languages
- containment of conjunctive queries
- disjunctive datalog
- databases
- fixpoint
- belief revision
- logic programs
- inconsistent databases
- algebraic operators
- knowledge base