Chapter 4 Building Conceptual Data Models

Creating a reflexive relationship

A reflexive relationship is a relationship between an entity and itself.

Example

The reflexive relationship Supervise expresses that an employee (Manager) can supervise other employees.


Note   Getting neat relationship lines
To obtain clean lines with rounded corners when you create a reflexive relationship, select Display Preferences→Format→Relationship and modify the Line Style with the appropriate type from the Corners dropdown listbox.

Steps To create a reflexive relationship:

  1. Click the Relationship tool in the Palette.
  2. Click inside the first entity and while continuing to hold down the mouse button, drag the cursor to a space next to the entity.
  3. Click the entity.

    A relationship symbol loops back to the same entity.

Note   Entity dependencies
In the Dependencies page of the entity, you can see two identical occurrences of the relationship, this is to indicate that the relationship is reflexive and serves as origin and destination for the link

 

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