Relational Query Languages
Query languages: Allow manipulation and retrieval of data from a database.
Relational model supports simple, powerful QLs:
- Strong formal foundation based on logic.
- Allows for much optimization.
Query Languages != programming languages!
- QLs not expected to be “Turing complete”.
- QLs not intended to be used for complex calculations.
- QLs support easy, efficient access to large data sets.