Declarative Database Query Language
A Declarative Database Query Language is a database query language (to composed database queries) that is a declarative language.
- Context:
- It can (typically) specify properties the Database Query Answer should satisfy (rather than give an algorithm to compute the answer).
- Example(s):
- See: Imperative Database Query Language, Database Query Optimization.
References
2017
- Jeffrey F. Naughton. (2017). “Broadening and deepening query optimization yet still making progress: technical perspective.” In: ACM Communications.
- QUOTE: Query optimization is a fundamental problem in data management. Simply put, most database query languages are declarative rather than imperative — that is, they specify properties the answer should satisfy, rather than give an algorithm to compute the answer. The best known and most widely used database query language — SQL — is a prime example of a language for which optimization is essential. By "essential," I mean that database optimization is not a matter of shaving 10% or even a factor of 2x from a query's execution time. In database query evaluation, the difference between a good plan and a bad or even average plan can be multiple orders of magnitude — so successful query optimization makes the difference between a plan that runs quickly and one that never finishes at all.