escape_identifiers() to accept arrays as well
diff --git a/system/database/drivers/mysqli/mysqli_forge.php b/system/database/drivers/mysqli/mysqli_forge.php
index e0e98f1..b74c775 100644
--- a/system/database/drivers/mysqli/mysqli_forge.php
+++ b/system/database/drivers/mysqli/mysqli_forge.php
@@ -152,7 +152,7 @@
 				if (is_array($key))
 				{
 					$key_name = $this->db->escape_identifiers(implode('_', $key));
-					$key = $this->db->protect_identifiers($key);
+					$key = $this->db->escape_identifiers($key);
 				}
 				else
 				{