Keyphrases
- query language
- data model
- expressive power
- relational algebra
- database
- query evaluation
- recursive queries
- visual query language
- semistructured data
- object oriented
- regular expressions
- complex objects
- conjunctive queries
- xml data
- transitive closure
- constraint databases
- aggregate functions
- normal form
- data integration
- object oriented databases
- relational databases
- graph databases
- knowledge base
- rdf data
- relational data model
- relational calculus
- query engine
- data mining
- data sets