Getting Started with InfoSphere Data Architect

62 Getting started with InfoSphere Data Architect
1. Display all key and non-key attributes in each entity:
a. Click on a blank part of the diagram. The properties of the diagram display in
the Properties view.
b. On the Filters tab of the Properties view, select the Show key and Show nonkey
check boxes.
2. Use the diagram to create a Non-Identifying Optional relationship from the
STUDENT entity to the GRADE entity:
a. In the palette, under the Data section, select the Non-Identifying Optional data
object.
b. In the diagram editor, select the STUDENT entity, drag the mouse cursor to
the GRADE entity, then release the mouse button.
c. Since the STUDENT ID attribute exists in both entities, you are asked to
specify how to address the attribute. In this case, choose the Replace with
migrated FK attribute/column option to ensure that both attributes are the
same.
The relationship is created in the model and depicted in the diagram. Now you should
describe the relationship. Remember that the diagram is just a visual representation of the
metadata in the model; therefore the relationship is also created in the logical data model.
When you “describe” this relationship, you explain with verb phrases how these entities
interact in the real world. In this case, you might explain that each student has more than
one grade, because they take more than one class. Also, a single grade is given to each
student for each class. Therefore, the cardinality of the relationship is a one-to-many
relationship.
3. Describe the relationship, using the Properties view:
a. Select the relationship object on the data diagram, as shown in Figure 3.10: