diff --git a/components/config/definition.rst b/components/config/definition.rst
index d3346a5f9fc..1b031e7bdaa 100644
--- a/components/config/definition.rst
+++ b/components/config/definition.rst
@@ -757,7 +757,7 @@ The builder is used for adding advanced validation rules to node definitions, li
                     ->scalarNode('driver')
                         ->isRequired()
                         ->validate()
-                        ->ifNotInArray(array('mysql', 'sqlite', 'mssql'))
+                            ->ifNotInArray(array('mysql', 'sqlite', 'mssql'))
                             ->thenInvalid('Invalid database driver %s')
                         ->end()
                     ->end()