Extending the Relational Algebra for Relations with Maybe Tuples and Existential and Universal Null Values.
Joachim BiskupPublished in: Fundam. Inform. (1984)
Keyphrases
- null values
- relational algebra
- relational calculus
- relational model
- normal form
- expressive power
- data model
- query language
- relational algebra expressions
- relational data model
- first order logic
- complex objects
- relational database systems
- integrity constraints
- functional dependencies
- relational databases
- database
- query evaluation
- transitive closure
- multi dimensional
- recursive queries
- aggregate functions
- database systems
- universal relation
- user defined
- databases