title: @GeneratedValue doesn't work at non id field
body: <p>I would like to make a unique field "number" with autogeneration(autoincrement, last number + 1). But it is not an id field. How can i reach that? @GeneratedValue doesn't work. Only id was generated. My code doens't work.</p>
  
  <p><strong>My entity</strong></p>
  
  <pre><code>@Entity
  @Table(schema = "public")
  public class Policeman implements Serializable {
  
      @Id
      @GeneratedValue
      private Long id;
  
      @Column
      @GeneratedValue(strategy = GenerationType.SEQUENCE)
      private Long number;
  
      @Column
      private String fam;
  
      @Column
      private String name;
  
      @Column
      private String otch;
  
     //setters getters
  }
  </code></pre>