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Old November 25th, 2011, 02:21 PM
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Rod Stephens Rod Stephens is offline
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I think that would work in this example, although it doesn't quite feel "right" somehow.

In this example I'm assuming that all customers, vendors, and employees must have Persons records. If you don't require that, then you couldn't use one ID for everything because you might, for example, want to create a Customer without a Person.

But if you assume that all three must have Persons records, then I thikn it would work.

(I think the difference is mainly philosophical. In the design with separate IDs you're thinking about Customers, Vendors, and Employees and the Persons table provides extra detail for them. If you use the PersonId everywhere, then you're thinking about Persons and the Customers, Vendors, and Employees tables provide additional detail for them.)
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