diff --git a/system/database/DB_active_rec.php b/system/database/DB_active_rec.php
index 35164a7..89369f1 100644
--- a/system/database/DB_active_rec.php
+++ b/system/database/DB_active_rec.php
@@ -38,7 +38,7 @@
  * @author		EllisLab Dev Team
  * @link		http://codeigniter.com/user_guide/database/
  */
-class CI_DB_active_record extends CI_DB_driver {
+abstract class CI_DB_active_record extends CI_DB_driver {
 
 	protected $return_delete_sql		= FALSE;
 	protected $reset_delete_data		= FALSE;
diff --git a/system/database/DB_driver.php b/system/database/DB_driver.php
index bcff433..79b7285 100644
--- a/system/database/DB_driver.php
+++ b/system/database/DB_driver.php
@@ -38,7 +38,7 @@
  * @author		EllisLab Dev Team
  * @link		http://codeigniter.com/user_guide/database/
  */
-class CI_DB_driver {
+abstract class CI_DB_driver {
 
 	public $dsn;
 	public $username;
@@ -1357,9 +1357,7 @@
 	 *
 	 * @return	void
 	 */
-	protected function _reset_select()
-	{
-	}
+	abstract protected function _reset_select();
 
 }