Keyphrases
- databases
- database
- database queries
- data sources
- query language
- relational database systems
- query processing
- data model
- response time
- web databases
- indexing techniques
- null values
- search interface
- relational database management systems
- relational databases
- data retrieval
- web search engines
- query evaluation
- statistical databases
- efficient processing
- data objects
- database systems
- search queries
- data collections
- query formulation
- database views
- query logs
- data integration
- data warehouse
- complex queries
- range queries
- retrieval systems
- user queries
- database applications
- knowledge discovery
- digital libraries
- answering queries
- keywords
- metadata