The one-to-many association is perhaps the most common one that you will encounter in database modeling. As an example, we will look at the enterprise of a medical clinic.

We wish to track the level of various substances (for example, cholesterol or alcohol) in the blood of patients. For each blood sample that is taken from the patient, one test will be performed and the date of the sample, the substance tested, and the measured level of that substance will be recorded in a database.

• Describe each class in English.

• Draw the class diagram.

• Describe each association in English (both directions).

• Draw the relation scheme.

The solution to this exercise will be discussed in class or posted online at a later date.

Copyright © 2002–2006, by Tom Jewett. Links to this site are welcome and encouraged. Individual copies may be printed for non-commercial classroom or personal use; however, this material may not be reposted to other web sites or newsgroups, or included in any printed or electronic publication, whether modified or not, without specific permission from the author.