实体可以访问存储库吗? [英] Can an Entity access a Repository?

问题描述

说，我有两个简单的实体:用户"和评论".如果用户调用评论"存储库有多严重?用户获得评论的干净"方式是什么?

Say I've got two simple entities: User and Review. How bad is it if User calls the Review repository? What is the "clean" way for the User to get its Reviews?

class User
{
    public function getReviews()
    {
        return reviewRepository.findByUser(this);
    }
}

我确实看过这个问题，但是，尽管他们说这是一种不好的做法，但我在那儿没有找到答案.

I did have a look at this question, but although they say this is a bad practice, I didn't find an answer there.

推荐答案

在DDD中，干净的方法是让UserRepository在询问用户时填充用户的评论.

The clean way in DDD is to have the UserRepository fill the reviews of the User when asking for a User.

class UserRepository
{
  public User GetUserByID(long userId)
  {
    var user = CreateUser();
    user.Reviews = FindReviewsforUser(userID);
    return user;
  }
}

但是在执行此操作之前，您需要验证您域中的用户实体也是AggregateRoot！只有AggregateRoots有存储库.请查看此问题，以查看或了解有关问题的信息在设计aggregateroots时.

But before you do this, you need to verify that your User Entity in your Domain is also an AggregateRoot! Only AggregateRoots have Repositories. Please take a look at this question to see or get some insights to the problems while desiging aggregateroots.

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