diff --git a/tiramisu/config.py b/tiramisu/config.py
index 4c830d2..536aacf 100644
--- a/tiramisu/config.py
+++ b/tiramisu/config.py
@@ -20,19 +20,14 @@
 # the rough pypy's guys: http://codespeak.net/svn/pypy/dist/pypy/config/
 # the whole pypy projet is under MIT licence
 # ____________________________________________________________
-from time import time
 from tiramisu.error import PropertiesOptionError, ConfigError
 from tiramisu.option import OptionDescription, Option, SymLinkOption, \
     BaseInformation
-from tiramisu.setting import groups, Settings, default_encoding, storage_type
+from tiramisu.setting import groups, Settings, default_encoding, get_storage
 from tiramisu.value import Values
 from tiramisu.i18n import _
 
 
-def gen_id(config):
-    return str(id(config)) + str(time())
-
-
 class SubConfig(BaseInformation):
     "sub configuration management entry"
     __slots__ = ('_impl_context', '_impl_descr', '_impl_path')
@@ -466,13 +461,6 @@ class CommonConfig(SubConfig):
     "abstract base class for the Config and the MetaConfig"
     __slots__ = ('_impl_values', '_impl_settings', '_impl_meta')
 
-    def _init_storage(self, config_id, is_persistent):
-        if config_id is None:
-            config_id = gen_id(self)
-        import_lib = 'tiramisu.storage.{0}.storage'.format(storage_type)
-        return __import__(import_lib, globals(), locals(), ['Storage'],
-                          -1).Storage(config_id, is_persistent)
-
     def _impl_build_all_paths(self):
         self.cfgimpl_get_description().impl_build_cache()
 
@@ -526,7 +514,7 @@ class Config(CommonConfig):
         :param context: the current root config
         :type context: `Config`
         """
-        storage = self._init_storage(config_id, is_persistent)
+        storage = get_storage(self, config_id, is_persistent)
         self._impl_settings = Settings(self, storage)
         self._impl_values = Values(self, storage)
         super(Config, self).__init__(descr, self)
@@ -566,10 +554,8 @@ class MetaConfig(CommonConfig):
                     raise ValueError(_("child has already a metaconfig's"))
                 child._impl_meta = self
 
-        if config_id is None:
-            config_id = gen_id(self)
         self._impl_children = children
-        storage = self._init_storage(config_id, is_persistent)
+        storage = get_storage(self, config_id, is_persistent)
         self._impl_settings = Settings(self, storage)
         self._impl_values = Values(self, storage)
         self._impl_meta = None
diff --git a/tiramisu/setting.py b/tiramisu/setting.py
index 3c649fe..58059d7 100644
--- a/tiramisu/setting.py
+++ b/tiramisu/setting.py
@@ -34,7 +34,7 @@ ro_append = ('frozen', 'disabled', 'validator', 'everything_frozen',
 rw_remove = ('permissive', 'everything_frozen', 'mandatory')
 rw_append = ('frozen', 'disabled', 'validator', 'hidden')
 default_properties = ('expire', 'validator')
-storage_type = 'dictionary'
+storage_type = 'sqlite3'
 
 
 class _const:
@@ -184,6 +184,22 @@ class Property(object):
         return str(list(self._properties))
 
 
+def set_storage(name):
+    global storage_type
+    storage_type = name
+
+
+def get_storage(context, config_id, is_persistent):
+    def gen_id(config):
+        return str(id(config)) + str(time())
+
+    if config_id is None:
+        config_id = gen_id(context)
+    import_lib = 'tiramisu.storage.{0}.storage'.format(storage_type)
+    return __import__(import_lib, globals(), locals(), ['Storage'],
+                      -1).Storage(config_id, is_persistent)
+
+
 #____________________________________________________________
 class Settings(object):
     "``Config()``'s configuration options"
@@ -202,7 +218,7 @@ class Settings(object):
         # generic owner
         self._owner = owners.user
         self.context = context
-        import_lib = 'tiramisu.storage.{0}.setting'.format(storage_type)
+        import_lib = 'tiramisu.storage.{0}.setting'.format(storage.storage)
         self._p_ = __import__(import_lib, globals(), locals(), ['Settings'],
                               -1).Settings(storage)
 
diff --git a/tiramisu/storage/dictionary/storage.py b/tiramisu/storage/dictionary/storage.py
index a7a135a..876f5da 100644
--- a/tiramisu/storage/dictionary/storage.py
+++ b/tiramisu/storage/dictionary/storage.py
@@ -24,6 +24,8 @@ from tiramisu.i18n import _
 
 class Storage(object):
     __slots__ = tuple()
+    storage = 'dictionary'
+
     def __init__(self, config_id, is_persistent):
         if is_persistent:
             raise ValueError(_('a dictionary cannot be persistent'))
diff --git a/tiramisu/storage/sqlite3/storage.py b/tiramisu/storage/sqlite3/storage.py
index efc730b..e9d5e08 100644
--- a/tiramisu/storage/sqlite3/storage.py
+++ b/tiramisu/storage/sqlite3/storage.py
@@ -25,6 +25,7 @@ import sqlite3
 
 class Storage(object):
     __slots__ = ('_conn', '_cursor', 'is_persistent', 'db_file')
+    storage = 'sqlite3'
 
     def __init__(self, config_id, is_persistent):
         self.is_persistent = is_persistent
diff --git a/tiramisu/storage/sqlite3/value.py b/tiramisu/storage/sqlite3/value.py
index 00be15c..af4164d 100644
--- a/tiramisu/storage/sqlite3/value.py
+++ b/tiramisu/storage/sqlite3/value.py
@@ -70,12 +70,12 @@ class Values(Cache):
         path = self._sqlite_encode_path(path)
         self.storage.execute("DELETE FROM value WHERE path = ?", (path,))
 
-    def get_modified_values(self, context):
+    def get_modified_values(self):
         """return all values in a dictionary
         example: {option1: (owner, 'value1'), option2: (owner, 'value2')}
         """
         ret = {}
-        for path, value, owner in self.storage.select("SELECT value",
+        for path, value, owner in self.storage.select("SELECT * FROM value",
                                                       only_one=False):
             path = self._sqlite_decode_path(path)
             owner = getattr(owners, owner)