● You can add an entity to a subtype cluster by choosing Insert > Relationship > Identifying, clicking the subtype cluster symbol next to the supertype you want to associate the entity with, and then clicking the entity you want to add to the subtype cluster.
● You can edit the subtype by right-clicking the subtype cluster symbol and then selecting Edit Subtype Cluster.
● You can change the colors of the subtype cluster symbol, by right-clicking it and then selecting Subtype Cluster Color.
● You can remove an entity from a subtype by selecting the relationship between the subtype and the entity and then choosing Edit > Remove Relationship.
● You can delete a subtype if you no longer want to include it in your data model. You can also add or remove entities from a subtype cluster in much the same way you add or delete relationships between entities. Delete a subtype by selecting the subtype and then choosing Edit > Delete Subtype Cluster. Deleting a subtype cluster deletes all relationships between the parent entity (supertype) and the child entities (subtypes).
● You must redefine the relationships between the entities after you delete a subtype.
● While subtypes can be specified as complete or incomplete, you’ll get a visual indication of it only in IDEF1X. To see the distinction in IE (Crow’s feet) you can view it in the Subtype Cluster Editor, or use a naming convention or color as a mnemonic.
● IE is more flexible in supporting subtypes, permitting roll up (generalization) and roll down (specialization) transformations.