Subclassing, Database Management System

In the ER diagram, one example of subclassing is depicted following the Services entity. The subclasses Item Based and Time Based are created. The entity Services gains the attribute priceID depending on the price of the service. For example, a time based service is measured hourly so its price is adjusted to the priceID. This information is gained and placed into the Service entity to make the Payments entity exist and function.

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