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    <p>Repository Layer gives you additional level of abstraction over data access. Instead of writing</p> <pre><code>var context = new DatabaseContext(); return CreateObjectQuery&lt;Type&gt;().Where(t =&gt; t.ID == param).First(); </code></pre> <p>to get a single item from database, you use repository interface</p> <pre><code>public interface IRepository&lt;T&gt; { IQueryable&lt;T&gt; List(); bool Create(T item); bool Delete(int id); T Get(int id); bool SaveChanges(); } </code></pre> <p>and call <code>Get(id)</code>. Repository layer exposes basic <strong>CRUD</strong> operations.</p> <p>Service layer exposes business logic, which uses repository. Example service could look like:</p> <pre><code>public interface IUserService { User GetByUserName(string userName); string GetUserNameByEmail(string email); bool EditBasicUserData(User user); User GetUserByID(int id); bool DeleteUser(int id); IQueryable&lt;User&gt; ListUsers(); bool ChangePassword(string userName, string newPassword); bool SendPasswordReminder(string userName); bool RegisterNewUser(RegisterNewUserModel model); } </code></pre> <p>While <code>List()</code> method of repository returns all users, <code>ListUsers()</code> of IUserService could return only ones, user has access to.</p> <p>In ASP.NET MVC + EF + SQL SERVER, I have this flow of communication:</p> <blockquote> <p><strong>Views &lt;- Controllers -> Service layer -> Repository layer -> EF -> SQL Server</strong></p> <p><strong>Service layer -> Repository layer -> EF</strong> This part operates on models.</p> <p><strong>Views &lt;- Controllers -> Service layer</strong> This part operates on view models.</p> </blockquote> <p><strong>EDIT:</strong> </p> <p>Example of flow for /Orders/ByClient/5 (we want to see order for specific client):</p> <pre><code>public class OrderController { private IOrderService _orderService; public OrderController(IOrderService orderService) { _orderService = orderService; // injected by IOC container } public ActionResult ByClient(int id) { var model = _orderService.GetByClient(id); return View(model); } } </code></pre> <p>This is interface for order service:</p> <pre><code>public interface IOrderService { OrdersByClientViewModel GetByClient(int id); } </code></pre> <p>This interface returns view model:</p> <pre><code>public class OrdersByClientViewModel { CientViewModel Client { get; set; } //instead of ClientView, in simple project EF Client class could be used IEnumerable&lt;OrderViewModel&gt; Orders { get; set; } } </code></pre> <p>This is interface implementation. It uses model classes and repository to create view model:</p> <pre><code>public class OrderService : IOrderService { IRepository&lt;Client&gt; _clientRepository; public OrderService(IRepository&lt;Client&gt; clientRepository) { _clientRepository = clientRepository; //injected } public OrdersByClientViewModel GetByClient(int id) { return _clientRepository.Get(id).Select(c =&gt; new OrdersByClientViewModel { Cient = new ClientViewModel { ...init with values from c...} Orders = c.Orders.Select(o =&gt; new OrderViewModel { ...init with values from o...} } ); } } </code></pre>
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    1. PODifference between Repository and Service Layer?
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    1. COThat's pretty similar to mine
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    2. CO@LukLed - Where do your View Models work at? I am thinking Controller serves the View Model to the View. The View Model get's it's data from the Service Layer, which gets it's data from the Repository, which quires the EF objects/POCO's. Does that sound correct?
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    3. COYes, that is how it works.
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A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

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