How do I insert nested objects correctly in Ef - sql

Question

I had a problem trying to add object from dto.
I have a DTO like this
public class CustomerCourseSessionDto : IDto
{
public int Id { get; set; }
public int? ConnectorId { get; set; }
public List<SomeObject>? SomeObject { get; set; }
public List<OtherObject>? OtherObject { get; set; }
}
and I'm trying to insert this DTO sent from the UI. I'm using a loop(foreach) for this, but it didn't feel right to me.
Maybe entityframework suggests a method for this, idk...
Other objects are like this
public class SomeObject: IEntity
{
public int Id { get; set; }
public int? ConnectorId { get; set; }
}
public class OtherObject: IEntity
{
public int Id { get; set; }
public int? ConnectorId { get; set; }
}
Thanks for the suggestions.
Here is where I use the loop:
[TransactionScopeAspect]
public IResult AddWithDto(CustomerCourseSessionDto courseSessionDto)
{
foreach (var item in courseSessionDto.Participants)
{
_someObjectService.Add(item);
}
foreach (var item in courseSessionDto.Lessons)
{
_otherObjectService.Add(item);
}
_customerCourseSessionDal.Add(new CustomerCourseSession
{
Id = courseSessionDto.Id,
CustomerCourseId = courseSessionDto.CustomerCourseId,
});
return SuccessResult with message ;
}

Answer 1

You should design your entities to have a link to each table using foreign keys.
public class CustomerCourseSession
{
public int Id { get; set; } // Primary Key
public string Name { get; set; }
public virtual ICollection<CourseParticipant> Participants { get; set; }
public virtual ICollection<CourseLesson> Lessons { get; set; }
}
public class CourseParticipant
{
public int Id { get; set; }
public int CustomerCourseSessionId { get; set; } // Foreign Key from CustomerCourseSession
// other fields here
public virtual CustomerCourseSession CustomerCourseSession { get; set;}
}
public class CourseLesson
{
public int Id { get; set; }
public int CustomerCourseSessionId { get; set; } // Foreign Key from CustomerCourseSession
// other fields here
public virtual CustomerCourseSession CustomerCourseSession { get; set;}
}
Then you can just call:
var entity = MapDtoToEntity(courseSessionDto);
_dbContext.CustomerCourseSessions.Add(entity);
_dbContext.SaveChanges();