You can generally find the solution to the problem by comparing your code to the completed code. Generally, it is a good idea to expose your Repository layer to a Service layer, which then provides domain entity objects to the UI & Business Layer. In order to enable your application to meet all the illities i.e. A plugin for Microsoft.EntityFrameworkCore to support repository, unit of work patterns, multiple database with distributed transaction supported, and MySQL multiple databases/tables sharding supported. EF repository. So, why do we need to add another layer of abstraction over the Entity Framework Core, which is … The domain/business logic layer contains the interfaces for a unit of work and a generic repository. In theory, you should inject your Unit of work into your repository classes. Repository and Unit of Work pattern implementation for Entity Framework Core 3. The idea being you could replace EF with another database access framework with no change to the methods that call the Repo+UOW. The following section shows how to implement repository methods that enable you to specify that this work should be done by the database. It was around this time, that it became rather fashionable to abstract the use of Entity Framework behind the Repository Pattern and Unit Of Work pattern. That in turn means that only the selected entities are returned by the database. While the repository pattern is often extended to include business logic (unrelated to persistence), it is often a cleaner approach to keep the repository pattern … The repository pattern is discussed extensively in the following resources and Patterns of Enterprise Application Architecture and Domain Driven Design. Once all updates of the aggregates in a scope are completed, the tracked changes are played onto the … (If you were using interfaces here, you wouldn't initialize the variable here; instead, you'd implement a pattern of two constructors just as you did for the Student repository.). Everything they say, is indeed valid in certain contexts, but then again in others they may be wrong. Using tools like EFCore gives us DBContext which already represents repository and UoW(Unit Of Work) implementation with very minimal effort. As in the previous tutorial, in this one you'll change the way your code works with pages you already created rather than creating new pages. Software developers use the repository pattern to separate the logic that retrieves the data and maps it to an entity model from the business logic that acts on the model. However, EF by itself already is a Unit of Work with Repositories (DbSet) built in. Having a single Unit or Work per request is necessary for the pattern to function correctly. It is implemented by the Repository and by all IConcreteRepository interfaces. Learning how and when to use any software pattern, is still far more important than just learning a pattern and implementing it everywhere. Entity Framework DBContext as Repository and UOW. The original version of this method contained the following code: The updated Index method contains the following code: In the original version of the code, students is typed as an IQueryable object. We will build a project right from scratch where we implement a clean architecture to access data. That way, when a unit of work is complete you can call the SaveChanges method on that instance of the context and be assured that all related changes will be coordinated. Replace the code you currently have in CourseController.cs with the following code: This code adds a class variable for the UnitOfWork class. For example, if the repository is instantiated for the Student entity type, the code in the calling method might specify q => q.OrderBy(s => s.LastName) for the orderBy parameter.