如何在 EF 核心中使用 OwnsMany 关系更新许多拥有的实体

Question

I am implementing a web api in .net 5 and ef core 5 using domain driven design. The problem is: I have a simple aggregate student and a value object Phones like

public class Student 
{
     public long Id{ get; private set; }
     public string FirstName { get; private set; }
     public string LastName { get; private set; }
     public IReadOnlyCollection<Phone> Phones { get; private set; }
}

public class Phone
{
   public string Key { get; private set; }
   public string Value { get; private set; }
}

How it works for example a student has two phones key phone with value 123345 and key mobile with value 2345678 etc

I am using fluent api to configure this relationship

class StudentConfiguration : IEntityTypeConfiguration<Student>
    {
        public const string StudentId = "StudentId";
        public const string Key = "Key";
        public void Configure(EntityTypeBuilder<Student> builder)
        {
            builder.ToTable("StudentsDB");
            builder.HasKey(x => x.Id);

            builder.Property(x => x.Id).ValueGeneratedNever().IsRequired();
            builder.Property(x => x.FirstName).HasMaxLength(25).IsRequired();
            builder.Property(x => x.LastName).HasMaxLength(50).IsRequired();

            builder.OwnsMany(
                x => x.Phones,
                builder =>
                {
                    builder.ToTable("Phones");
                    builder.Property<long>(StudentId).IsRequired();

                    builder.WithOwner().HasForeignKey(StudentId);

                    builder.Property(x => x.Key).IsRequired();
                    builder.Property(x => x.Value).IsRequired();

                    builder.HasKey(StudentId, Key);
                });
        }
    }

and now the problem is, I have a business requirement to be able a student to change phones, all or one of them(the simplest approach I consider if a student change the one phone, internal in my api replace the two phones, one with the new values and the other with old values)

But now I don't know how to achieve this... The update method update the whole student entity, when I try to call the collection aw navigation then i don't know how to continue..

public async Task UpdatePhones(Student student)
        {           
#warning must fix it , it update the whole entity
            //var studentEntry = context.Attach(student);
            context.Update(modification.Student);

            //var phoneEntries = studentEntry.Collection(e => e.Phones);
            //phoneEntries.IsModified = true;

            await context.SaveChangesAsync();
        }

Note: the simplest approach I consider if a student change the one phone, internal in my api replace the two phones, one with the new values and the other with old values

Answer 1

You can try to use following code

  var s1= await _context.Students.Where(x => x.Id == student.Id).SingleAsync();
  s1.Phones = student.Phones;
  _context.Update(s1);
  await _context.SaveChangesAsync();