Now, using Visible Analyst®, or another CASE tool, create an ERD that shows the two main entities in Danica’s shop, and the relationship between them. Add an associative entity if necessary.
What will be an ideal response?
A sample answer might use an associative entity such as WORK ASSIGNMENT. In this example one and only one mechanic receives one or many assignments. In other words, assignments are given on an individual basis, not as a team, even though several mechanics might work together.
Similarly, one, or many WORK ASSIGNMENTS can include a specific JOB. Thus, Eduardo, a mechanic, could receive a work assignment that listed four separate jobs to perform on a certain automobile. Or, Eduardo might receive four separate work assignments, each for a single job on a different vehicle. Students should see that WORK ASSIGMENT is an associative entity, much like GRADE, which links STUDENTS and CLASSES in Figure 9-26 on page 299. The sample ERD follows:
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