Keyphrases
- query language
- query processing
- query evaluation
- relational calculus
- efficient processing
- database queries
- web search engines
- database
- attribute values
- range queries
- data objects
- set valued attributes
- complex queries
- relational algebra
- query logs
- retrieval systems
- response time
- data sources
- information retrieval
- semantic relations
- query formulation
- binary relations
- answering queries
- relational data model
- databases