diff --git a/system/database/drivers/cubrid/cubrid_driver.php b/system/database/drivers/cubrid/cubrid_driver.php
index f80b4db..65f4adb 100644
--- a/system/database/drivers/cubrid/cubrid_driver.php
+++ b/system/database/drivers/cubrid/cubrid_driver.php
@@ -187,25 +187,17 @@
 	/**
 	 * Begin Transaction
 	 *
-	 * @param	bool	$test_mode
 	 * @return	bool
 	 */
-	public function trans_begin($test_mode = FALSE)
+	protected function _trans_begin()
 	{
-		// When transactions are nested we only begin/commit/rollback the outermost ones
-		if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
+		if (($autocommit = cubrid_get_autocommit($this->conn_id)) === NULL)
 		{
-			return TRUE;
+			return FALSE;
 		}
-
-		// Reset the transaction failure flag.
-		// If the $test_mode flag is set to TRUE transactions will be rolled back
-		// even if the queries produce a successful result.
-		$this->_trans_failure = ($test_mode === TRUE);
-
-		if (cubrid_get_autocommit($this->conn_id))
+		elseif ($autocommit === TRUE)
 		{
-			cubrid_set_autocommit($this->conn_id, CUBRID_AUTOCOMMIT_FALSE);
+			return cubrid_set_autocommit($this->conn_id, CUBRID_AUTOCOMMIT_FALSE);
 		}
 
 		return TRUE;
@@ -218,19 +210,16 @@
 	 *
 	 * @return	bool
 	 */
-	public function trans_commit()
+	protected function _trans_commit()
 	{
-		// When transactions are nested we only begin/commit/rollback the outermost ones
-		if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
+		if ( ! cubrid_commit($this->conn_id))
 		{
-			return TRUE;
+			return FALSE;
 		}
 
-		cubrid_commit($this->conn_id);
-
 		if ($this->auto_commit && ! cubrid_get_autocommit($this->conn_id))
 		{
-			cubrid_set_autocommit($this->conn_id, CUBRID_AUTOCOMMIT_TRUE);
+			return cubrid_set_autocommit($this->conn_id, CUBRID_AUTOCOMMIT_TRUE);
 		}
 
 		return TRUE;
@@ -243,16 +232,13 @@
 	 *
 	 * @return	bool
 	 */
-	public function trans_rollback()
+	protected function _trans_rollback()
 	{
-		// When transactions are nested we only begin/commit/rollback the outermost ones
-		if ( ! $this->trans_enabled OR $this->_trans_depth > 0)
+		if ( ! cubrid_rollback($this->conn_id))
 		{
-			return TRUE;
+			return FALSE;
 		}
 
-		cubrid_rollback($this->conn_id);
-
 		if ($this->auto_commit && ! cubrid_get_autocommit($this->conn_id))
 		{
 			cubrid_set_autocommit($this->conn_id, CUBRID_AUTOCOMMIT_TRUE);