title: Choose relation one to many or many to one for design
body: <p>I need help to define the relationship between the models.</p>
  
  <p><strong>I have 2 models :</strong></p>
  
  <ol>
  <li>User </li>
  <li>Product</li>
  </ol>
  
  <p>The user own many products and the product is owned by only one user.</p>
  
  <p><strong>My use case :</strong> 
  The logged user can access to some information in his personnal account : 
  - Display all his products
  - Add a new product</p>
  
  <p>Later i'd like to add use case like : any user can see any product in some screen (and know product's owner).</p>
  
  <p>So, i can define the models like that :</p>
  
  <p><strong>A) ONE TO MANY</strong></p>
  
  <pre><code>class User{
  
  private Set&lt;Product&gt; products;
  ..
  }
  
  class Product{
  
  ...
  } 
  </code></pre>
  
  <p><strong>B) MANY TO ONE</strong></p>
  
  <pre><code>class User{
  
   ..
  }
  
  class Product{
  
   private User owner;
  }
  </code></pre>
  
  <p><strong>Which is the best ? one to many or many to one ?</strong></p>
  
  <p>Because my use case display the product of logged user Im thinking its better to choose <strong>one to many</strong></p>