Keyphrases
- relational algebra
- query language
- relational model
- expressive power
- relational database systems
- data model
- structured query language
- database language
- normal form
- relational databases
- complex objects
- relational calculus
- first order logic
- null values
- relational data model
- boolean algebra
- aggregate functions
- recursive queries
- database
- set theory
- databases
- sql queries
- database query languages
- modal logic
- logic programming
- classical logic
- database design
- algebraic structure
- query evaluation
- relation algebra
- algebraic operators
- database applications
- data exchange
- functional dependencies
- incomplete information
- predicate logic
- transitive closure
- database queries
- database management
- conjunctive queries
- stored procedures
- relational database management systems
- relational dbms
- programming language
- visual basic