Keyphrases
- query evaluation
- xpath queries
- database
- query language
- probabilistic databases
- data complexity
- response time
- query processing
- web search engines
- efficient processing
- user queries
- constraint databases
- data sources
- query logs
- query complexity
- conjunctive queries
- answering queries
- databases
- query formulation
- database queries
- query answering
- retrieval systems
- data model
- complex queries
- range queries
- query terms
- aggregate queries
- language model
- web search
- unions of conjunctive queries