title: Favorite constraint for navigation property in Entity Framework
body: <p>So I have <code>Student</code> model and 'Subject' model. And there is one-to-many relation between <code>Student</code> and <code>Subject</code>. <code>Subject</code> model itself created by student, so each <code>Subject</code> has 1-1 relation to <code>Student</code>.</p>
  
  <p>Right now, when I trying to request something like <code>Student.Subjects</code> it return's me all <code>Subjects</code> created by this user. But I need to add favorite logic.</p>
  
  <p>So right now, Student could mark 'Subject' as <em>favorite</em> (Even if this Subject wasn't construct by this Student.)</p>
  
  <p>My question is how should I organize data structure to support <code>Student.FavoritesSubjects</code> (It could be multiple favorite subjects for the user)</p>
  
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  <p>UPD: And what is difference if only <code>Student's</code> own <code>Subject</code> could be marked Favorite. Is this allow to avoid many-to-many relation?</p>