Relationships and Domains › Relationships in the Logical Model › Subtype Relationships in the Logical Model

Subtype Relationships in the Logical Model

When you analyze the entities in your model, you may have some entities that define an entire type, or classification of a particular item. In a data model, you can show that full time and part time employees are part of a larger category, EMPLOYEE, by creating a subtype relationship. A subtype relationship connects an entity that defines the category and two or more additional entities that define each of the elements of the category. The parent entity of the category is considered the supertype and each child entity is considered a subtype.

You can create the following types of subtype relationships:

• Complete subtype relationship (in IDEF1X, when all categories are known).
• Incomplete subtype relationship (in IDEF1X, when all categories may not be known).
• Inclusive subtype relationship (in IE, when an attribute in the subtype entity can derive its value from one or more subtype entities).
• Exclusive subtype relationship (in IE, when an attribute in the subtype entity can derive its value from only one subtype entity).

You can also add a verb phrase for the subtype relationships in your model. You use a discriminator as the verb phrase for a subtype relationship.

More information:

Assign a Discriminator to a Subtype Relationship