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One-to-many relationships - Exercise

Objective: Identify one-to-many relationships.

Exercise Scoring

For this exercise, correctly complete each phase of the exercise as described in the instructions below.

Background and Overview

In the preceding lessons, you learned that a one-to-many relationship exists when, for one instance of entity A, there exists zero, one, or many instances of entity B; but for one instance of entity B, there exists zero or one instance of entity A. You also learned that 1:N relationships are common in the business world, and that most databases are comprised almost entirely of 1:N relationships. Finally, you learned that the many side of a 1:N relationship receives the key attribute to establish the link.


All four entities that exist for Stories on CD, Inc. are in a one-to-many relationship: CUSTOMER, ORDER, CD, and DISTRIBUTOR.
Specifically, CUSTOMER and ORDER are in a 1:N relationship, as are CD and DISTRIBUTOR (ORDER and CD are in a many-to-many relationship, discussed later in the module). Your task in this exercise is to: (1) Provide an appropriate business or common-sense rule for each 1:N relationship; (2) specify the relationship values within the rule; and (3) indicate which entity in each relationship receives the key attribute.
Use the following example to understand these tasks. Imagine that EMPLOYEE and DEPARTMENT are in a 1:N relationship as defined by a specific business rule. The format to use in providing your answer looks like this:

An employee is assigned to a department (1:1); a department has many employees (1:N).
DEPARTMENT receives the key attribute from EMPLOYEE.


In addition to applying common-sense rules, be sure to read the case study available for download from the following link Download Case Study
You might find a business rule (or two) there that is applicable to your task, and remember, if you are having challenges trying to verbalize the relationships, then draw tables.

Submitting your exercise

Type or paste your answers into the text box below, then click Submit to submit them and view a results page.