Why use repository with entity framework

Windows 11 is Here. Read what is new in Windows Mukesh Kumar Updated date Dec 07, Step 1: Start Visual Studio or Select ASP. Provide the Name and Location for the project and click Next. Choose Basic template as project template and click OK. Models; using System; using System.

Generic; using System. In my last project I simply created an interface for the dbContext class that exposes the tables, savechanges function, and any other extras I might need.

The repository abstraction has another purpose. The layer using the repository would not change and would not be aware of where and how the data it received was constructed. I don't fully agree. EF is a very specific implementation of how you access data. Having an abstraction between your application and data access is vital. What if you decide to change ORMs or have several data sources as eranotzap suggested? Regardless of EF not being very testable, it should not be the only reason to use an abstraction to EF.

Show 5 more comments. This picture makes it easy to understand. Sanjeewa Sanjeewa 1 1 gold badge 7 7 silver badges 17 17 bronze badges. The db context in EF follows the Unit of Work pattern and each collection is similar to a repository. You can create a very simple wrapper around the context and still unit test. Espen Burud Espen Burud 1, 10 10 silver badges 9 9 bronze badges.

Isn't when I use entity framework to query an order object, the order will contains a list of order lines? Sorry I am getting confuse In the EF you can also save and retreive a complete aggregate root object with the ObjectContext.

SaveChanges method. But I wrote it because it's one of the advantages with the repository pattern. I see, now I understand.

Whoever comes across this should know that the repository pattern is an anti-pattern. Ayende explains why: youtube. SamDev thank you - it's taken me hours of surfing the web to find someone who can articulate why the proliferation of repository code I keep seeing gives me an ill feeling in my stomach.

Show 1 more comment. Using repositories in combination with UnitOfWork can centralize this logic too. Jowen Jowen 4, 1 1 gold badge 40 40 silver badges 40 40 bronze badges.

Repository systems are good for testing. One reason being that you can use Dependency Injection. Jordan Jordan 2, 3 3 gold badges 19 19 silver badges 34 34 bronze badges. Trystan Spangler Trystan Spangler 1, 11 11 silver badges 20 20 bronze badges.

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NET or React. The first three items are all around performance. For me the read part, known as a query in EF Core, are often the hardest to build and performance tune. Many applications rely on good, fast queries such as, a list of products to buy, a list of things to do, and so on. The answer that people have come up with is query objects. The listing below gives a simple example of a query object that can select the order in which a list of integers is sorted.

The MyOrder query object works because the IQueryable type holds a list of commands, which are executed when I apply the ToArray method. In the code below uses four query objects chained together to select, sort, filter and page the data on some books. The query objects handle the read part of the CRUD, but what about the Create, Update and Delete parts, where you write to the database? Note: If you want to try adding a review you can do that. To run the ASP. NET Core application then a clone the repo, select branch Chapter05 every chapter has a branch and run the application locally.

You will see an Admin button appear next to each book, with a few CUD commands. The most obvious approach is to use EF Core methods to do the update of the database.

Here is a method that would add a new review to a book, with the review information provided by the user. Note: the ReviewDto is a class that holds the information returned by the user after they have filled in the review information. This will add the new review to the database. It works, but there is another way to build this using a more DDD approach.

EF Core offers us a new place to add your update code to — inside the entity class. Backing fields allow you to control access to any relationship.