4.3

Maxima

The greatest number of instances of one entity that can relate to a single instance of another entity.

Minima

The least number of instances of one entity that can relate to a single instance of another entity.

Cardinality

A relationship between two entities that indicates how many instances of one entity can or must be associated with instances of another entity.

Unique Attribute

An attribute that has at most one entity instance for each attribute value, distinguishing it from a singular attribute.

Singular Entity

An entity relation that has a maximum of one related instance.

Plural Entity

An entity relation that has a maximum of many related instances.

Attribute Maximum

The number of attribute values that can describe each entity instance.

Attribute Minimum

The least number of attribute values that can describe each entity instance.

Optional Related Entity

When the minimum is zero, indicating that the relationship is not mandatory.

Required Related Entity

When the minimum is one, indicating that the relationship is mandatory.

Entity

A thing with distinct existence, recognized within the context of a specific domain.

Attribute

A characteristic or property of an entity.

Instance

A specific realization of an entity type, representing a single occurrence.

Relationship

A connection between two or more entities.

One-to-One Relationship

A relationship where a single instance of one entity is related to a single instance of another entity.

One-to-Many Relationship

A relationship where a single instance of one entity can be associated with multiple instances of another entity.

Many-to-Many Relationship

A relationship where multiple instances of one entity can be associated with multiple instances of another entity.

Foreign Key

An attribute that creates a link between two tables, referencing a primary key from another table.

Primary Key

A unique identifier for a record in a table, ensuring that each instance is distinct.

Normalization

The process of organizing data in a database to reduce redundancy and improve data integrity.