Analyzing Data › Defining Entity Types, Relationships, and Attributes › Defining Relationships › Relationship Name

Relationship Name

The name of a relationship membership describes the reason for joining two entities of the entity types participating in the relationship.

The name is a verb (either active or passive) that connects one entity type (the subject of a sentence) to another (the object of a sentence).

For example, places and is placed by are the relationship membership names in the following illustration.

The use of is a matter of style. Some analysts omit is to give shorter relationship names that are more likely to display fully on diagrams. Others prefer to use is placed by, not only placed by. Using is in this example not only makes for a better sentence here, but it also reads well in the syntax of action diagrams.

With simply the relationship membership names in place, the relationship can be described as follows:

• Customer places order
• Order is placed by customer

  CA Gen makes an arbitrary distinction between relationship memberships, which are based on the order in which the analyst chooses the entity types participating in the relationship. The relationship membership that is associated with the entity type chosen first is named the source membership, while the other is named the destination membership. This distinction merely provides a means for selecting individual memberships when using CA Gen; it does not imply a direction to a relationship.