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    <p>If I understand your schema correctly, you have an <code>Address</code> table with a discriminator column, <code>addressTypeID</code>, which defines which kind of <em>Address</em> that particular record represents. The single <code>Address</code> table contains both types of records...<strong>Billing</strong> and <strong>Shipping</strong> addresses. If this is the case, then you actually have a Table-Per-Hierarchy, or TPH, structure, since there is <em>one table per class hierarchy</em>.</p> <p>You mentioned that you thought you had a Table-Per-Concrete-type, or TPC, structure. If that were the case, then your database would require both <code>ShippingAddress</code> and <code>BillingAddress</code> tables, since in TPC, there is <em>one table per concrete type</em>.</p> <p>You would need to have a code structure similar to the following:</p> <pre><code>public abstract class Address { // Common address properties } public class ShippingAddress: Address { // Additional shipping-address specific properties } public class BillingAddress: Address { // Additional billing-address specific properties } </code></pre> <p>You would then need to map your class hierarchy of <code>ShippingAddress</code> and <code>BillingAddress</code> types as a TPH mapping on your single <code>Address</code> table, discriminated on the <code>addressTypeID</code> column. The AddressType column would not even play a role in the mapping, unless you wished to map by some AddressType name or surrogate key. In that case, a view that presents a merged view of the appropriate Address and AddressType tables would be your base TPH schema source, with the discriminator column being the surrogate key column included from the AddressType table.</p>
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    1. POEntity Framework 4.0 Creating a new entity derived from other entities
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    1. USjrista
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    1. COjrista another question. If we continue in this example and wanted to have a User class which contains both a BillingAddress and a ShippingAddress, how would we model this in Entity Framework. I don't want a collection of Address classes, I want 2 distinct Associations to the same table. How can we accomplish this?
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      1. USKen Burkhardt
    2. CO@Ken: It should be as easy as simply having two properties of the appropriate types. The ORM framework should be intelligent enough to detect which type is being used and, via your model/mapping configuration, generate the appropriate query.
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