Dependency theory is a subfield of
database theory which studies implication and optimization problems related to logical constraints, commonly called dependencies, on databases.
The best known class of such dependencies are
functional dependencies, which form the foundation of
keys
Key or The Key may refer to:
Common meanings
* Key (cryptography), a piece of information that controls the operation of a cryptography algorithm
* Key (lock), device used to control access to places or facilities restricted by a lock
* Key (m ...
on database relations. Another important class of dependencies are the
multivalued dependencies. A key algorithm in dependency theory is the
chase
Chase or CHASE may refer to:
Businesses
* Chase Bank, a national bank based in New York City, New York
* Chase Aircraft (1943–1954), a defunct American aircraft manufacturing company
* Chase Coaches, a defunct bus operator in England
* Chase C ...
, and much of the theory is devoted to its study.
Dependencies
*
functional dependency
*
join dependency
*
multivalued dependency
*
tuple-generating dependency
*
equality-generating dependency
*
embedded dependency
*
inclusion dependency
Referential integrity is a property of data stating that all its references are valid. In the context of relational databases, it requires that if a value of one attribute (column) of a relation (table) references a value of another attribute ( ...
*
full typed dependency
{{database-stub
Database theory
Database constraints