Figure 4-8: Straight Relationships
Notice that in Figure 4-8, even with the lines straight, it is not clear what the model is about. What is the “subject” of the model? Expected measurement? Sample? It’s hard to tell.
Orienting the relationship lines so that the “..*” ends are at the left or toward the top of the diagram makes that clearer, as shown in Figure 4-Error! Bookmark not defined..
Figure 4-9: Properly Oriented Relationships
Here, the “reference” entity classes, that describe relatively tangible things (Test Type, Person, and Sample, for example), tend to collect in the lower right, ...