title: Annotation for unique constraint for single column
body: <p>I would like to instruct Hibernate to create unique constraint on a single column. I have set <code>hibernate.hbm2ddl.auto=update</code> in the hibernate configuration and my code is shown below:</p>
  
  <pre><code>@Column(name = "program_id",unique=true)
  @Length(min = 0, max = 10)
  private String programID;
  </code></pre>
  
  <p>I don't see any unique index created on the table in MySQL. What am I suppose to do to get it working ?</p>