Relationships and Domains › Relationships in the Logical Model › Add a Hierarchical Recursive Relationship

Add a Hierarchical Recursive Relationship

You can add a hierarchical recursive (single-table recursion) relationship in a logical model when a parent entity or table can have any number of children, but a child can only have one parent. Perform the following steps to add a hierarchical recursive relationship:

1. Click the Entity icon on the erwin Toolbox, then click anywhere on the diagram window.
2. Name the parent entity or table and add the primary and non-key attributes or columns.
3. Click the Non-identifying Relationship icon on the erwin Toolbox.
4. Click the parent entity or table, pause briefly, then click the entity or table again.
5. Double-click the relationship line to open the Relationships editor.
6. Click the General tab, and enter a verb phrase to explain the recursive relationship.
7. Click the Rolename tab, assign a descriptive rolename to the migrated foreign key attributes or columns based on the relationship, then click OK to close the Relationships editor.