When a primary key attribute or an alternate key attribute migrates from a parent entity to a child entity, it becomes a foreign key attribute in the child entity. Since a foreign key can have a different role than the role of the related primary key or alternate key, you can assign a rolename to a foreign key attribute. You assign a rolename to a foreign key to describe its role in a particular entity and to distinguish it from another attribute with the same name.
Use the options in the Rolename tab in the Relationships editor to define attribute rolenames for relationships in a logical model.
To assign a rolename to an attribute
The Relationships editor opens.
The Rolename tab opens.
Lets you select the primary key or the alternate key that migrates from the parent entity to the child entity.
Displays the primary key attribute or the alternate key attribute that is migrated from the parent entity to the child entity and the rolename associated with the attribute in the current relationship.
Lets you enter a rolename for the attribute you selected from the Migrated Attribute/Rolename list.
The rolename is assigned. When working in a Logical/Physical model, you have the option to apply the rolename to the physical model. When prompted, click Yes to apply the rolename to the physical side of the model. Click No to apply the rolename only on the logical side.
Note: The rolename is displayed as the migrated key. When you select the Rolename/Attribute entity display option, a period is inserted after the rolename and before the basename.
Copyright © 2017 erwin Inc.
All rights reserved.
|
|