title: Can I have a one-many relationship between a super-type and each sub-type?
body: <p>I am trying to model a scenario where I have a SuperType that has 2 Sub-types.  However, each Sub-Type has several records associated with an instance of the Super-Type.</p>
  <p>Let's say there is a Book and there are 2 types of Books and each type of book has 3 parts with different details.</p>
  <p>Book is a SuperType. The Poem is a SubType and Short-Stories is another SubType. The book may either be an anthology of poems or short stories.</p>
  <p>A Book of Type Poem has 3 Poems with each Poem having a different author but all 3 tied to the same Book Id.  Similarly, the book can also be a compilation of Short-Stories and each book can have many Short-Stories.</p>
  <pre><code>Book
  Book1   Book1_Details
  Book2   Book2_Details
  Book3   Book3_Details
  Book4   Book4_Details
  
  Poem 
  Book1   Poem1  Author1
  Book1   Poem2  Author2
  Book1   Poem3  Author3
  Book2   Poem4  Author4
  Book2   Poem5  Author5
  Book2   Poem6  Author6
  </code></pre>
  <p>Similarly, Book 3 and Book 4 have 3 Short stories each.</p>
  <p>What is the right way to model this?</p>
  <pre><code>Book
  BookId BookDetails
  
  Poem
  BookId EachPoemId EachPoemDetails
  </code></pre>
  <p>or do I need a third entity</p>
  <pre><code>Book
  BookId BookDetails
  
  BookPoem
  BookPoemId BookId PoemCollectionId
  
  Poem
  EachPoemId PoemCollectionId EachPoemDetails
  </code></pre>
  <p>Does each super-type have to have 1-1 between with a sub-type as in a person can either be a student or staff? How do I model the scenario that a book can be many poems or many stories?</p>