Keyphrases
- integrity constraints
- constraint language
- deductive databases
- logic rules
- knowledge representation
- constraint checking
- query answering
- conjunctive queries
- knowledge base
- semantic web
- integrity checking
- functional dependencies
- database schema
- inclusion dependencies
- database integrity
- xml documents
- schema integration
- null values
- active rules
- ontology languages
- xml schema
- consistent query answering
- distributed databases