Database Principles - Chapter 7: Normalising Database Designs

A collection of flashcards derived from the lecture notes on database normalisation, covering key concepts, definitions, and processes essential for understanding database design.

Normalisation

The process for evaluating and correcting table structures to minimise data redundancies.

1NF (First Normal Form)

A normal form that ensures all key attributes are defined and there are no repeating groups in the table.

2NF (Second Normal Form)

A normal form that is in 1NF and contains no partial dependencies.

3NF (Third Normal Form)

A normal form that is in 2NF and contains no transitive dependencies.

BCNF (Boyce-Codd Normal Form)

A normal form where every determinant in the table is a candidate key.

4NF (Fourth Normal Form)

A normal form that is in 3NF and has no multiple sets of multivalued dependencies.

Denormalisation

The process of combining tables in a database to improve processing speed at the cost of data redundancy.

Data Anomaly

An inconsistency that arises in a database when there are multiple representations of the same data.

Primary Key

A unique identifier for a record within a table.

Transitive Dependency

When one non-key attribute depends on another non-key attribute.

Partial Dependency

When a non-key attribute is dependent on only a part of a composite primary key.

Dependency Diagram

A visual representation of dependencies within a table.

Entity-Relationship (ER) Diagram

A macro view of an organization’s data requirements and operations.

Attribute Atomicity

The requirement that attributes in a database table should store indivisible values.

Surrogate Key

A unique identifier for an entity that is not derived from an application data model.

Multivalued Dependency

When one attribute in a table determines multiple values of another attribute.

Anomalies

Issues that occur when inserting, updating, or deleting data in a database.

Candidate Key

An attribute, or set of attributes, that can uniquely identify a record in a table.