updating drupal schema

I have an install file in place which create开发者_JAVA百科s a table when the module is first enabled. Halfway into the use of the module, I want to update the table with an additional column I write the code for it as

'salary' => array(
  'description' => t('Salary: '),
  'type' => 'int',
  'unsigned'=> TRUE,
  'not null' => TRUE,
),

This goes within the schema definition. Now to add it to the database , I use the update function as

function test_update_6001(){
  $ret = array();
  $spec = array(

  'description' => t('Salary: '),
  'type' => 'int',
  'unsigned'=> TRUE,
  'not null' => TRUE,

  );
  db_add_field($ret,'info','salary',$spec);  //info is the tablename and salary is the column to be added

  return $ret;
  drupal_install_schema('stalker');
}

This is not updating the schema. Am i missing a step?

Make sure you include it in the original hook_schema() function and not just in the update function.

You don't need to call the drupal_install_schema after the return, but it's not the cause anyway. There's no error when you run the update.php script?