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    <p>I believe you <strong>really should</strong> add a <code>TEntity GetById(int id)</code> to your <code>IRepository&lt;TEntity&gt;</code> generic interface.</p> <p>Why? Because if you don't, and if you want to fetch a single record on your business layer, you only have two options (on the repository, data-access layer):</p> <ol> <li>Return a complete, "unlazy" collection, meaning that you'll return, say, 100,000 records in order to use a single one.</li> <li>Return a lazy collection like <code>IQueryable&lt;TEntity&gt;</code>, which, yes, will allow you to get a single record from the database, but may cause a lot of <a href="http://www.weirdlover.com/2010/05/11/iqueryable-can-kill-your-dog-steal-your-wife-kill-your-will-to-live-etc/" rel="nofollow noreferrer">nasty side-effects</a>.</li> </ol> <p>The first option is clearly wrong. The second is controversial, but (unless your project has you as a single developer, and you really really really know what you're doing) it is potentially leaky and unsafe. So, if you do need a single record (and sometimes you'll surely do), expose a method that does exactly that.</p> <p>Having said that, you should also <strong>not</strong> expose <code>IQueryable&lt;TEntity&gt; All { get; }</code>, for exactly the same reasons above. Use <code>IEnumerable&lt;TEntity&gt; All { get; }</code> instead, and make your concrete generic repository class return a real collection, by calling <code>context.Set&lt;TEntity&gt;().ToList()</code> for instance.</p> <p><strong>Edit</strong></p> <p>Regarding IDisposable:</p> <p>There are only two (related) reasons for implementing the IDisposable interface that I can think of:</p> <ol> <li>Disposing unmanaged resources</li> <li>A cool way of <a href="http://www.peterprovost.org/blog/post/RAII-and-IDisposable-and-Thoughts-About-OO.aspx" rel="nofollow noreferrer">implementing the RAII pattern</a>.</li> </ol> <p>In your case, you probably <em>should</em> use it on your repository implementation. Please take a look at <a href="https://stackoverflow.com/questions/2975760/should-linq-to-sql-repository-implement-idisposable">this SO question</a> for further information.</p>
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    1. CO@null: I'll edit my answer, please take a look at it.
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    2. CO-1, Although you have good insight into GetById, it wasn't the answer to any of the OP's questions.
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    3. CO@Levitikon: he asked about `IDisposable` and I answered it. That's 1 answer (at least that's how I learned to count, not sure about you :P)
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