Database Design: Relation Predicates and “Identical Relations”(dbdebunk.com)

  (RENAME(A, a_id TO a_or_b_id) UNION RENAME(B, b_id TO a_or_b_id))

  class Person { public string Name { get; set; } }
  ...
  var employees = new List<Person>(...);
  var managers = new List<Person>(...);

  class Person { public string Name { get; set; } }
  class Employee : Person {}
  class Manager : Person {}
  ...
  var employees = new List<Employee>(...);
  var managers = new List<Manager>(...);