Logical Data Modeling - Aggregation (Collection)

Data System Architecture

About

aggregation is a containment relationship where one or more entities are part of a container entity.

In other word, aggregation is combining multiple pieces of data into one unit.

The container entity may be:

aggregation is also known as:

  • whole/part relationship
  • catalog containment because when the container is destroyed, the content object is not destroyed (whereas in a composition it is).

In other term, this is not a dependency relationship (whereas a composition is)

The container is said to be an aggregate/compound type.

The structure to implements this kind of relationship is known as a collection.

Example

  • Library and Students. Because the student can exist without library, the relation between student and library is aggregation.
  • professor and students: when the professor dies the students do not die along with him or her.

Property

A aggregation is:

Visualization

In a Object - Class Diagram (UML), an aggregation is represented with an association (ie the link) with a hollow diamond at the aggregate end.

1..*1Professor+ listOfStudents : listClass+ Students : list

Magical Number Seven, Plus or Minus Two

Nominal - Magical Number Seven, Plus or Minus Two

Operations

See Function - (Aggregate | Aggregation)





Discover More
Data System Architecture
(Collection|Container) Data Type (Set, Bag, Sequence)

A collection is a abstract data type for grouping together multiple values. It's therefore sometime known as a container and creates a aggregation relationship A collection is: an object that groups...
1..*1Professor+ listOfStudents : listClass+ Students : list
Class - Aggregation Relationship

aggregation relationship in code. Library and Students. Because the student can exist without library, the relation between student and library is aggregation. professor and students: when the...
Card Puncher Data Processing
Data Processing - Operations / Operator / Filter

A data processing function takes an input and creates an output in a pipeline. transition in Automata functional interface in Functional Programming Filter in Data Processing (Shell and Log Pipeline)...
Model Funny
Function - (Aggregate | Aggregation)

Aggregate functions return a single value calculated or selected from values that are in a aggregation relationship (ie a set) This values are also known as summary because they try to summarize...
Data System Architecture
Logical Data Modeling

A data model in software engineering is a graph of entity that try to represent the reality and describes how data are represented and accessed. the real world consists of entities and relationships....
Data System Architecture
Logical Data Modeling - Aggregate Data

Aggregate data are data that are in a aggregation relation (ie elements that are in a collection) An aggregate function is a function that is applied to aggregate data (ie A sum is applied to a collection...
Association Entity Example
Logical Data Modeling - Association

An association is a relationship between two or more entities. It's represented by a link in the data model. An association: answers to the question why two entity need to know one another. specifies...
Data System Architecture
Logical Data Modeling - Classification (Taxonomy | Categorization) - Transversal Data Organization

Classification is an naming technique for organization where entity or relationship gets classified by giving them a nominal attribute known as a classifier. relationshipsgroups or categories The output...
Data System Architecture
Logical Data Modeling - Classifier (Label, Class, Tag) - Descriptif Attribute

A label is an attribute that describes its entity or relationship with nominal data. A label is also known as: a tag a class or just a nominal attribute a classifier a group a category Classifiers...
Uml Composite Aggregation
Logical Data Modeling - Composition Relationship

composition is a containment relationship of physical type where the content entity is a part of a container entity This relationship is also known as: a whole/part relationship (ie whole/component)...



Share this page:
Follow us:
Task Runner