title: The property 'BookId' on entity type 'Library' has a temporary value. Either set a permanent value explicitly or ensure that the database is
body: <p>When I use Entity Framework Core and seed data with migration, I have this error:</p>
  
  <blockquote>
    <p>The property 'BookId' on entity type 'Library' has a temporary
    value. Either set a permanent value explicitly or ensure that the
    database is configured to generate values for this property.</p>
  </blockquote>