My Hero Zero

My Hero Zero

The Data Model Scorecard™ contains over 400 rules to apply when reviewing a data model. One of these rules requires justifying optionality on a relationship. For example, on this model


We have these two business rules:

  • Each Customer can place many Orders.
  • Each Order must be placed by one Customer.

The circle on the relationship line implies zero. That is, a Customer can exist without ever placing an Order. In this example, we would ask the modeler the question, “When can a Customer exist without having placed an Order?”

Someone during a recent training class on the Scorecard asked why it is important to justify optionality such as in this example. Why do you think it is important?

Read the response to this challenge