Keyphrases
- selectivity estimation
- query optimization
- spatial join
- r tree
- join algorithms
- query processing
- b tree
- xml queries
- database systems
- cost model
- index structure
- spatial databases
- tree structure
- tree structures
- sql queries
- query execution
- relational database systems
- continuous queries
- query plan
- xml data
- spatial objects
- efficient processing
- database schema
- metric space
- join operations
- query optimizer
- spatial data