Keyphrases
- relational algebra
- database language
- relational databases
- query language
- sql queries
- data exchange
- relational model
- database design
- databases
- cd rom
- modal logic
- database
- database applications
- back end
- expressive power
- inclusion dependencies
- null values
- classical logic
- normal form
- database technology
- incomplete information
- asynchronous circuits
- data model and query language
- query answering
- ibm db
- data model
- multi valued
- database queries
- programming language
- data integration
- database schema
- temporal logic