Razer Technology Solutions, Inc.

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Exton, PA 19341
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n-ary Data Modeling: Physical Modeling of the Ternary

Lets start by taking a look at the physical model of the Employee-Project-Skills schema.

The employee-project-skills relationship will be driven in part by an entity that links what
employees are assigned to a project, the skills they have and the skills that are required for a
project. We need to keep in mind that since our employee-skills relationship exists outside of the
the other entities, we will need to model it as well. How would we determine what skills a particular
employee is using on a project? In essence, what role are they filling on the project? Without the
table in the middle, we would not be able to extract this information. The Staffing table represents
the crux of the ternary relationship between the three major entities.


figure 3: physical model of the transactional ternary

The above physical model represents one possible implementation of the ternary. In this example,
we've actually over-modeled the logical representation a bit. Our next step would be to whittle the
redundant data relationships out and create a set of concise tables that will serve our application.

More to Come: An n-ary transactional model.