Normalization Flashcards
A technique for producing a set of relations with desirable properties, given the data requirements of an enterprise.
Normalization
occurs when a user who wants to insert data about one real-world entity is forced to enter data about another real-world entity.
Insertion anomaly
occurs when a user who wants to delete data about a real-world entity is forced to delete data about another real-world entity.
Deletion anomaly
occurs when, in order to modify one value, the same modification has to be made multiple times.
Modification anomaly
The sets of rules to eliminate
anomalies, and produce a new
collection of problem-free tables.
Normal forms
Types of Normal Forms
- First Normal Form (1NF)
- Second Normal Form (2NF)
- Third Normal Form (3NF)
- Boyce-Codd Normal Form (BCNF)
Normalization - Fourth Normal Form (4NF)
- Fifth Normal Form (5NF)
- Domain Key Normal Form (DKNF)
Describes the relationship between
attributes in a relation.
Functional dependency
An attribute or collection of attributes whose values determine the values of another attribute.
determinant
Indicates that if A and B are attributes of a relation, B is fully functionally dependent on A if B is functionally dependent on
A, but not on any proper subset of
A.
Full Functional Dependency
A condition where A, B and C are attributes of a relation such that A -> B and B -> C, then C is transitively dependent on A via B (provided that A is not functionally dependent on B or C).
Transitive Dependency
A table or relation is in ________ if it contains a repeating group.
Unnormalized Form
An attribute or group of attributes within a table that occurs with multiple values for a single occurrence of the nominated key attribute(s) for that table.
Repeating Group
A table or relation is in ________ if it does not contain repeating groups.
First Normal Form
A table or relation is in _________ if it is in 1NF and every non-key attribute is fully functionally dependent on the primary key (no partial dependencies).
Second Normal Form
A table or relation is in ____________ if it is in 2NF and no non-key attribute is transitively
dependent on the primary key.
Third Normal Form