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copied!<h3>Virtual vs. Final properties:</h3> <p>This has really nothing to do with code first, it's the topic of EF and POCOs: When you have POCOs you lose a bunch of EF supports for your navigation properties and you can opt in to them by making them virtual. This lets EF to make a proxy at runtime and give you the support by overriding the nav properties in that proxy class. Those supports are <em>Change Notification</em>, <em>Relationship Fixup</em> and <em>Lazy Loading</em>. </p> <p>Lazy Loading works the same for Collection and non Collection type navigation properties. Also it's considered to be a <em>good practice</em> to always mark your navigation properties as virtual.</p> <h3>Foreign Key Association or Independent Associations</h3> <p>EF3.5 does not support FKs in the associations and makes them hidden (a.k.a <em>Independent Associations</em>). EF4 starts to support FKs in the associations (a.k.a <em>Foreign Key Association</em>). Depend on which one you like, you can explicitly include or not include FK properties, but it's definitely a good practice to explicitly specify FK properties, in addition to navigation properties since it gives you ultimate flexibility to work with your objects.</p> <blockquote> <p>Upon retrieval, myAccountInstanceFromDb.Owner is null. Why is that? How do I tell EF that it should do its magic and populate my Owner property?</p> </blockquote> <p>Of course, you didn't marked it as virtual so Lazy Loading is not supported yet you did not explicitly eager load or defer load it as well. To resolve that either use <em>virtual</em> keyword and let EF lazy load it for you or use <em>Include</em> method to eager load it at the time the whole object is materialized.</p> <h3>Scalar properties vs. Navigation properties</h3> <p><em>Scalar properties</em> are properties whose values are literally contained in the entity and correspond with the table columns (e.g. Account.Id). <br> <em>Navigation properties</em> are merely <em>pointers</em> to the related entities. For example the Account entity has an Owner property that will enable the application to navigate from an Account to the Owner that owns that Account. <br> So, back to your question, all you need to do is to specify a navigation property as <code>virtual Person Owner</code> and <em>optionally</em> specify a FK property as <code>int OwnerId</code> and you are good to go. </p>

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