实体框架核心外键很多

Question

I'm using Entity Framework Core in context of a ASP.Net Core MVC application. A snippet of the data model looks like that:

public class Seminar
{       
   public int ID { get; set; }
   public string Name { get; set; }
   public Person Teacher { get; set; }
   public int TeacherID { get; set; }

   public IList<Person> Students { get; set; }

   public Seminar()
   {
      Students = new List<Person>();
   }
}

EF automatically assigns the property TeacherID to reflect the ID of the entity Teacher (foreign key). This is quite handy to be used in ASP.Net. Is there any similar concept for the to-many-reference Students ?

At the end I would like to create a multi-select in ASP.Net. Hence, I need a list of IDs of assigned Students to this seminar.

Answer 1

EF will infer the one-to-many relationship thanks to the IList<Person> Students navigation property, and it will refer to Students with that name. That is assuming that Person has a foreign key for Seminar . But then Person should also have a foreign key for seminar as a Teacher, so in the end that should be a many-to-many reationship, which requires a fluent API definition. Refer to this for more info

Answer 2

You can do it by fluent api

modelBuilder.Entity<Seminars>()
.HasMany(c => c.Students)
.WithOptional()
.Map(m => m.MapKey("StudentId"));