HOPEX Information Architecture > Data Architecture > The data model > Associations
Associations
 
Creating an Association
Defining association roles (ends)
Multiplicities
Other association characteristics
Aggregation
Composition
Using reflexive associations
Displaying an N-ary Association
*An association is a relationship that exists between two or more entities. It can carry attributes that characterize the association between these entities
Associations can be compared to links between index cards.
The following drawing provides a three-dimensional view of the situations a data diagram can store.
Peter and Mary are clients. Peter has made reservations numbers 312 and 329.
A data diagram should be able to store all situations in the context of the company, but these situations only.
*The diagram should not allow representing unrealistic or aberrant situations.
Examples of associations:
• A client issues an order.
• An order includes several products.
• A person works for a company.
• An alarm is triggered by a sensor.
• A sensor covers a zone.
• A window displays a string of characters.