title: Where is IDbSet<T> in entity core
body: <p><a href="https://i.stack.imgur.com/noyBE.png" rel="noreferrer"><img src="https://i.stack.imgur.com/noyBE.png" alt="enter image description here"></a></p>
  
  <pre><code>public abstract class RepositoryBase&lt;T&gt; : IRepository&lt;T&gt; where T : class
  {
      private ShopCoreDbContext dbContext;
      private readonly DbSet&lt;T&gt; dbSet; //here
      protected IDbFactory DbFactory { get; private set; }
      protected ShopCoreDbContext DbContext
      {
          get =&gt; dbContext ?? (dbContext = DbFactory.Init());
      }
      protected RepositoryBase(IDbFactory dbFactory)
      {
          DbFactory = dbFactory;
          dbSet = DbContext.Set&lt;T&gt;();
      }
      public virtual T Add(T entity)
      {
          return dbSet.Add(entity); //err here
      } 
  }
  </code></pre>
  
  <p>With IDbSet nothing happen. But IDbSet interface no longer exists in entity core. This is error detail:</p>
  
  <blockquote>
    <p>cannot implicitly convert type  Microsoft.entityframeworkcore.changetracking.entityentry to T</p>
  </blockquote>
  
  <p>It requires it must be an interface.<br>
  So what should I do now?</p>