/**
* HOWTO: 
* Copy this into a custom module, adjust the hook function {yourcustommodule}_views_data_alter
* accordingly and flush caches *twice* ... 
*/

/**
 * Designate a column of a mysql view as primary key.
 * This is required to expose a view via views (and data.module). 
 * 
 * @param string $dbview_name 	name of the database view 
 * @param string $pseudo_pk			name of the column acting as primary key
 * @param array $views_data 		array passed into hook_views_data_alter
 * @return bool	false on error 
 */
function _mysql_views_designate_primarykey($dbview_name, $pseudo_pk, &$views_data) {
  $tables = data_get_all_tables();
  // Sanity checking 
  if (!isset($tables[$dbview_name]) || !isset($views_data[$dbview_name])) {
    drupal_set_message( t('MySQL view @dbview_name could not be found in the views data or data.module registries!', array('@dbview_name'=>$dbview_name)), 'error');
    return false;
  }
  if (!isset($views_data[$dbview_name][$pseudo_pk])) {
    drupal_set_message( t('Field @pseudo_pk could not be found in the views data registry for view @dbview_name!', array('@dbview_name'=>$dbview_name, '@pseudo_pk'=>$pseudo_pk)), 'error');
    return false;
  }
  $table = $tables[$dbview_name];
  // Expose the database view as a base table for views. 
  $views_data[$dbview_name]['table']['base'] = array(
    'field' => $pseudo_pk,
    'title' => $table->get('title'),
    'help' => t('Data table'),
    'weight' => 10, 
  );
  // Designate a primary key for data.module. 
  // We run into a problem here: If you don't add the primary key,
  // data_ui_views_default_views() won't pick up on the table. If you do add
  // it, the schema comparison (admin/build/data/compare) will be confused. 
  $schema = $table->get('table_schema');
  $schema['primary key'] = array($pseudo_pk);
  $table->update( array('table_schema'=>$schema) ); 
  return true;   
}


function {yourcustommodule}_views_data_alter(&$views) {
  // name of the database view
  $dbview_name = 'voting_results';
  $pseudo_pk = 'item_id'; 
  _mysql_views_designate_primarykey($dbview_name, $pseudo_pk, $views);
  // name of the database view
  $dbview_name = '_tmp_voting_AARGH';
  $pseudo_pk = 'item_id'; 
  _mysql_views_designate_primarykey($dbview_name, $pseudo_pk, $views);
}