大模型存储库服务模式的正确实现

Question

I have a dilema implementing the repository service pattern in my C# WPF MVVM project where I have a big dataset in my model.

I used EntityFramework database first where I have created about 40 entities, so my model is quite large and for me it does not make sense to implement 40 different repositories, due to this I made use of the generic repository service pattern.

My Repository looks like the following:

  public interface IEntityRepository<T> : IDisposable where T : class
  {
    IQueryable<T> FindBy(Expression<Func<T, bool>> predicate);
    IEnumerable<T> getEntities();
    T RetrieveEntity(int entityID);
    void CreateEntity(T entity);
    void UpdateEntity(T entity);
    void DeleteEntity(T entity);
    void Save();
  }

And here is the signature of the class implementing the methods.

    public class EntityRepository<T> :
     IEntityRepository<T> where T : class
    {
      private DbContext context;
      public EntityRepository(DbContext context)
      {
        this.context = context;
      }          

       .....

    }

My question now is, how would the service look like so that I don't have to implement it for every single entity in my model. I'm looking for something like that I can dymanically create the service by the type name of the entity.

Does anyone knows a solution for my problem? Thanks!

Answer 1

I'm not convinced the repository pattern is a useful layer if your repository classes map one to one with your physical database entities.

You might be better with a service layer or other type of facade. You might also find success using the query pattern if you insist on a data access layer on top of the entity framework. In this pattern each query class could have a parameter object defining the parameters you can query your model on. Where the returned data is structured more suitable for consumption in the business or user interface layer. Each query object is then relevant to some part of your business or user interface layer. The query pattern can then be used when you have to query your data beyond accessing single entities.