Modeling Generalizations

Creating a New First Generalization Relationship

Prerequisites

Both entities involved already exist in the diagram.

How to proceed

Select the entity in the diagram that should be the sub-entity for the generalization relationship.

The carousel appears next to the entity.
Drag the desired generalization relationship from the carousel and drop the icon on the super-entity.

A new generalization relationship and generalization set are created in the diagram. If the super-entity has a key, a suitable foreign key automatically appears in the sub-entity, including the foreign attribute with the primary property.

Extending a Generalization Set with a New Generalization Relationship

Prerequisites

The super-entity's generalization set and future new sub-entity already exist in the diagram.

How to proceed

Select the entity in the diagram that should be the new sub-entity.

The carousel appears next to the entity.
Drag the desired generalization relationship from the carousel and drop the icon on the generalization set.

A new generalization relationship is created for the generalization set in the diagram. If the super-entity has a key, a suitable foreign key automatically appears in the sub-entity, including the foreign attribute with the primary property.

Assigning a Generalization Relationship to Another Generalization Set

Prerequisites

You can only assign a generalization relationship to a generalization set of the same super-entity. Both generalization sets are visible in the diagram.

How to proceed

Select the generalization relationship in the diagram on the side of the sub-entity.

The handle appears on the edge for the generalization set so you can reassign it.
Drag the handle to the desired generalization set.

The generalization relationship is reassigned to the new generalization set in the diagram. If the old generalization set has no more generalization relationships after this, then it is deleted in the model. The sub-entity's foreign key does not change.

Merging Two Generalization Sets

Prerequisites

You can only merge generalization sets of the same super-entity. Both generalization sets are visible in the diagram.

How to proceed

Drag a generalization set in the diagram and drop it on another one.

All generalization relationships (including those not visible in the diagram) are assigned to the target set. The moved generalization set is deleted. All of the sub-entity's foreign keys do not change.