diff --git a/system/database/drivers/pdo/pdo_forge.php b/system/database/drivers/pdo/pdo_forge.php
index 8c22eb3..e77970c 100644
--- a/system/database/drivers/pdo/pdo_forge.php
+++ b/system/database/drivers/pdo/pdo_forge.php
@@ -35,8 +35,15 @@
  */
 class CI_DB_pdo_forge extends CI_DB_forge {
 
+	/**
+	 * DROP TABLE statement
+	 *
+	 * @var	string
+	 */
 	protected $_drop_table		= 'DROP TABLE %s';
 
+	// --------------------------------------------------------------------
+
 	/**
 	 * Create Table
 	 *
diff --git a/system/database/drivers/pdo/pdo_utility.php b/system/database/drivers/pdo/pdo_utility.php
index ed4d685..03b3092 100644
--- a/system/database/drivers/pdo/pdo_utility.php
+++ b/system/database/drivers/pdo/pdo_utility.php
@@ -35,12 +35,10 @@
  */
 class CI_DB_pdo_utility extends CI_DB_utility {
 
-	protected $_list_databases = FALSE;
-
 	/**
-	 * PDO Export
+	 * Export
 	 *
-	 * @param	array	Preferences
+	 * @param	array	$params	Preferences
 	 * @return	mixed
 	 */
 	protected function _backup($params = array())