C#•2mo ago

Should I use navigation properties in EF Core?

When using EF Core should I always use navigation properties or never? for example I have:

class Post
{
  public string Content { get; set; }
  public string AuthorId { get; set; }
  public User Author { get; set; } // Should I use it?
}

class Post
{
  public string Content { get; set; }
  public string AuthorId { get; set; }
  public User Author { get; set; } // Should I use it?
}

class User
{
  public string Name { get; set; }
  public ICollection<Post> Posts { get; set; } // Should I use it?
}

class User
{
  public string Name { get; set; }
  public ICollection<Post> Posts { get; set; } // Should I use it?
}

I use .NET 9 in my smaller project and I wonder if it's better to use it or not in terms of performance?

14 Replies

Jimmacle•2mo ago

navigation properties are a major part of EF, if your entities have a relationship you conventionally model it by defining navigation properties

N_58OP•2mo ago

but as i've seen there's an option to omit them

Jimmacle•2mo ago

yes, you don't have to use them

N_58OP•2mo ago

and I just wondered if it's good idea, better or what

Keswiik•2mo ago

You can have both, which is what I do.

Jimmacle•2mo ago

it's much more convenient to use navigation properties in a query than writing explicit joins

N_58OP•2mo ago

and should i use virtual aswell?

Jimmacle•2mo ago

no performance differences to mention that i'm aware of

N_58OP•2mo ago

it uses lazy loading then, right?

Jimmacle•2mo ago

no, that's related to lazy loading which you should never use

N_58OP•2mo ago

oh, why not? 🤔

Jimmacle•2mo ago

because it causes surprise synchronous IO when you're accessing properties of what looks like a normal C# object ideally you use a .Select in your query to project out just the data you actually want, all in one go

N_58OP•2mo ago

alright, thanks i guess 😅 that explains a bit

Keswiik•2mo ago

public class SomeEntity {
  public int Id { get; set; }

  public int? NavPropertyId { get; set; }
  public SomeOtherEntity? NavProperty { get; set; }
}

public class SomeEntity {
  public int Id { get; set; }

  public int? NavPropertyId { get; set; }
  public SomeOtherEntity? NavProperty { get; set; }
}

^ this is also valid in EF, gives you the ability to reference nav properties in your queries, but also explicitly use the relational columns if you want to

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Should I use navigation properties in EF Core?

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