Keyphrases
- databases
- database
- query language
- database queries
- data retrieval
- query processing
- data sources
- indexing techniques
- relational database systems
- positive and negative
- efficient processing
- response time
- relational database management systems
- data model
- aggregate queries
- query logs
- complex queries
- statistical databases
- web databases
- database applications
- data management
- data warehouse
- knowledge discovery
- horn theories
- null values
- relational databases
- query formulation
- query evaluation
- query interface
- web search engines
- user queries
- data integration
- np hard
- database systems
- database objects
- spatio temporal databases
- bitmap indexes
- search queries