The Categorization relationship line is divided into three sections:

The Super-sub relationship line is not divided, but consists of a super-sub relation symbol only.

The origin of the relation line; the entity whose Primary Key components become Foreign Keys and Primary Key components in the Subtype. (Read only property)

The destination of the relation line; the recipient of Foreign Keys from this relationship. In a Super-sub relation, the primary key of the supertype is the primary key of the subtype. (Read only property)

The character to be used to group multiple super-sub relationships into exclusive sets. Please note that this property has the “text length of 1" therefore, only single-byte languages, such as English, should be used. Double-byte characters are not supported within this property. Double-byte characters are mostly used in Asian languages, such as Korean and Japanese.

In the example above, a PERSON can be an EMPLOYEE or a STUDENT (one super-sub relationship). A STUDENT “is a” PROSPECT, a CURRENT STUDENT, or a FORMER STUDENT (one sub relationship); OR an ALUMNUS (a different sub relationship). The two different sub relationships of STUDENT are grouped together through the character. The differentiation is similar to a menu with 2 columns, from which you may select one from Column A and one from column B. In Column A are all those sub-entities within one exclusive set; in Column B are all those sub-entities within a different exclusive set. In the example above, one could (in the real world) chose A SPECIFIC STUDENT “is a” a FORMER STUDENT OR AN ALUMNUS; you could not choose CURRENT STUDENT or PROSPECT, since those 2 are in the same exclusive relationship.

The key of the relationship line, whose components are the diagram name, the super-entity name and its GUID. The Category Discriminator is the attribute that differentiates between instantiations of the category. To include it in the definition, click the Differentiator between Subtypes popup for the Categorization. Click Choices, and then drag the appropriate attribute into the Discriminator box.

The actions to be taken by the database when a user attempts to insert, update or delete a record involved in this relationship. These properties are transferred to the appropriate constraints when a Physical Data Model is created from an ERD.