title: JPA: default column name mapping for @ManyToOne relations
body: <p>When we have a class:</p>
  
  <pre><code>@Entity
  Order implements Serializable {
      @Id
      private Integer id;
      ...
  }
  </code></pre>
  
  <p>and:</p>
  
  <pre><code>@Entity
  OrderLine implements Serializable {
      @Id
      private Integer id;
  
      @ManyToOne
      Order order;
      ...
  }
  </code></pre>
  
  <p>What <em>row name</em> will the property <strong>order</strong> map to?</p>
  
  <p><code>order_id, ORDER_ID or Order_id?</code></p>
  
  <p><strong>(ommiting the @JoinColumn(name='order_id') is deliberate)</strong></p>