title: Codeigniter Show Individual Custom Error
body: <p>I am trying to validate my login form and I have rules on my Username and Password fields.</p>
  
  <pre><code>$this-&gt;form_validation-&gt;set_rules('username', 'Username', 'trim|required|xss_clean');
  $this-&gt;form_validation-&gt;set_rules('password', 'Password', 'trim|required|xss_clean|callback_check_database');
  </code></pre>
  
  <p>So my <strong>callback_check_database</strong> function is on the Password field.  </p>
  
  <p>So in my function for check_database, I have:</p>
  
  <pre><code>$this-&gt;form_validation-&gt;set_message('check_database', 'Invalid username or password');
  return false;
  </code></pre>
  
  <p>So I am setting the custom message that I want to display.</p>
  
  <p>In my view, I want to individually show that check_database error.  I don't want to show any of the other errors.</p>
  
  <p>Here is what I have tried:</p>
  
  <pre><code>// does not work
  &lt;?php echo form_error('check_database'); ?&gt;
  
  // this works
  &lt;?php echo form_error('password'); ?&gt;
  </code></pre>
  
  <p>so since it is for the Password field, it will only show when I echo the password errors.  But that means, since password is a required field, if I don't type anything in it's going to display an error saying that the Password field is required.</p>
  
  <p>Is there a way to only display my custom error message that I set?</p>