Keyphrases
- query evaluation
- query language
- database
- data management
- random graphs
- query processing
- data complexity
- efficient query evaluation
- conjunctive queries
- null values
- database systems
- signature file
- databases
- query answers
- xml data
- probabilistic databases
- graph theoretic
- data model
- expressive power
- relational databases
- database queries
- bayesian networks
- querying xml documents