Database Normalization

Candidate key

relation schema has more than one key

Normal Form

Condition using keys and FDs of a relation to certify whether a relation schema is in a particular normal form

Constraints

Conditions that must hold on all valid relation

First Normal Form

Disallos composite attributes, multivalued attributes and nested realtions

Second Normal Form

Full functional dependency and partial functional dependency

Key Constraint

No two tuples in any valid relation state have the same values for primary key

Entity integrity constraint

The primary key attributes of each relation schema cannot have null values in any tuple

Normalization

The process of decomposing unsatisfactory "bad" relations by breaking up their attributes into smaller relations

Functional dependency

constraints that are derived from the meaning and interrelationships of the data attributes

Third Normal Form

Transitive functional dependancy

Superkey

a set of attributes with the property that no two tuples will equal eachother

Referential integrity constraint

specify a relationship among tuples in two relations, and is identified by a foreign key in one relation and the primary key of the referenced relation

Denormalization

the process of storing the join of higher normal form relations as a base relation