Keyphrases
- relational algebra
- expressive power
- relational model
- query language
- data model
- normal form
- null values
- relational calculus
- relational database systems
- complex objects
- first order logic
- relational databases
- relational data model
- database query languages
- relational operators
- transitive closure
- aggregate functions
- database
- summary tables
- relational algebra expressions
- algebraic operations
- recursive queries
- high level
- machine learning