Adding an entity in EF Core - entity-framework-core

Question

I am using EF Core db first approach, .NET6. I have the following classes:
public class Doctor
{
[Key]
public int DoctorId { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string Specialization { get; set; }
public string Phone { get; set; }
public string Email { get; set; }
public string Designation { get; set; }
public bool IsDeleted { get; set; }
}
and
public class Patient
{
[Key]
public int PatientId { get; set; }
[Required]
public string FirstName { get; set; }
public string LastName { get; set; }
public string Email { get; set; }
public string NIC { get; set; }
public string Phone { get; set; }
public string Address { get; set; }
public string City { get; set; }
public string Country { get; set; }
public DateTime DOB { get; set; }
public string Gender { get; set; }
public string Reference { get; set; }
public short SerialNumberYear { get; set; }
public int SerialNumber { get; set; }
[Required]
public int DoctorId { get; set; } //need to assign Primary doc. Is this correct?
public Doctor Doctor { get; set; }
public DateTime CreatedOn { get; set; }
public DateTime UpdatedOn { get; set; }
public string CreatedBy { get; set; }
public List<Doctor> SecondaryDoctors { get; set; }//need to assign a list of secondary docs. is this correct?
public bool SMS_Allowed { get; set; }
public bool Email_Allowed { get; set; }
public string SpecialConcern1 { get; set; }
public string SpecialConcern2 { get; set; }
public string SpecialConcern3 { get; set; }
public string SpecialConcern4 { get; set; }
}
The Patient class needs to have a Primary doctor assigned and a list of Secondary doctors assigned. What entries should I make in the Patient class to accomodate this requirement? I tried the entries shown above with comments. Is that correct? When I add a patient with this code, I get the following error when creating a new patient record:
Duplicate entry '1' for key 'doctors.PRIMARY'
So when creating a patient, why is efcore trying to create a doctor record?