private void UpdateSubjectRelationship(int bookCod, List <Subject> newSubjects, List <Subject> oldSubjects)
{
if (bookCod <= 0)
{
return;
}
List <Subject> subsToAdd = newSubjects
.Where(o => !oldSubjects
.Any(n => n.SubjectCod == o.SubjectCod))
.ToList();
if (subsToAdd.Any())
{
_subjectRepository.AddManyRelations(bookCod, subsToAdd);
}
List <Subject> subsToDelete = oldSubjects
.Where(o => !newSubjects
.Any(n => n.SubjectCod == o.SubjectCod))
.ToList();
if (subsToDelete.Any())
{
_subjectRepository.DeleteManyRelations(bookCod, subsToDelete);
}
}