Consider two classes.
public class File
{
[Key]
public string Id { get; set; }
public string Message_Id { get; set; }
internal Message Message { get; set; }
}
public class Message
{
[Key]
public string Id { get; set; }
}
In EF6, for N : 1..0 relation there was this fluent API.
modelBuilder.Entity<File>()
.HasOptional(e => e.Message ).WithMany().HasForeignKey(e => e.Message_Id);
What is equivalent in Entiity Framework Core 1?
Thank you
You will not find an equivalent method in EF 7. By convention, a property whose CLR type can contain null
will be configured as optional. So what decide if the relationship is optional or not is if the FK property is nullable or not respectively.
In summary, due to your Message_Id
FK property is string
, it already accepts null
value, so if you use the following Fluent Api configuration:
modelBuilder.Entity<File>()
.HasOne(s => s.Message)
.WithMany()
.HasForeignKey(e => e.Message_Id)
EF will configure your relationship as optional (or N : 0..1 as requested).
In case of your FK property is value type like int
, you should declare it as nullable (int?
).
Also I noticed now you have a navigation property with internal
access modifier. You should always declare your entity properties as public
.