The model has been constructed using the ministry's data model standards and conventions, and was designed using the ministry's standard data modeling software. Each of the three subject areas in the model contains a number of rectangular boxes and connecting lines. The boxes are called Entities , and the lines are called Relationships . This additional information is described by the Attributes of an entity. A relationship is an association that exists between entities.
Cardinality appears at both ends of the relationship.
There are only four cardinality types. Associative entities are diagrammed as a diamond within a rectangle. The symbols used in the data model are illustrated below. In order to read the model in this example, we construct a sentence around these constructs. The following descriptions are examples of some of the business rules and most of the key concepts represented by the data model.