diff --git a/lodel/datasource/mongodb/datasource.py b/lodel/datasource/mongodb/datasource.py
index 7100d59..ae13b31 100644
--- a/lodel/datasource/mongodb/datasource.py
+++ b/lodel/datasource/mongodb/datasource.py
@@ -38,13 +38,7 @@ class MongoDbDataSource(GenericDataSource):
     # @return dict
     # @TODO Change the return value using the Lodel 2 settings module
     def _get_connection_args(self, connection_name):
-        return {
-            'host': 'localhost',
-            'port': 27017,
-            'login': 'login',  # TODO modifier la valeur
-            'password': 'password',  # TODO modifier la valeur
-            'dbname': 'lodel'
-        }
+        return {'host': 'localhost', 'port': 28015, 'login': 'lodel_admin', 'password': 'lapwd', 'dbname': 'lodel'}
 
     ## @brief checks if the connection args are valid and complete
     # @param connection_args dict
@@ -59,7 +53,7 @@ class MongoDbDataSource(GenericDataSource):
         if len(errors) > 0 :
             raise MongoDbDataSourceError("\r\n-".join(errors))
 
-        return (connection_args['login'], urllib.quote_plus(connection_args['password']), connection_args['host'],
+        return (connection_args['login'], connection_args['password'], connection_args['host'],
                 connection_args['port'], connection_args['dbname'])
 
     ## @brief returns a selection of documents from the datasource
diff --git a/lodel/datasource/mongodb/migration_handler.py b/lodel/datasource/mongodb/migration_handler.py
index 9301fc9..960b5c3 100644
--- a/lodel/datasource/mongodb/migration_handler.py
+++ b/lodel/datasource/mongodb/migration_handler.py
@@ -2,10 +2,14 @@
 
 from lodel.datasource.generic.migrationhandler import GenericMigrationHandler
 from lodel.datasource.mongodb.datasource import MongoDbDataSource
+import lodel.datasource.mongodb.utils as utils
 from lodel.editorial_model.components import EmClass, EmField
+
+
 class MigrationHandlerChangeError(Exception):
     pass
 
+
 ## @brief Modifies a MongoDb database given editorial model changes
 class MongoDbMigrationHandler(GenericMigrationHandler):
 
@@ -19,6 +23,7 @@ class MongoDbMigrationHandler(GenericMigrationHandler):
             # del conn_args['module']
 
         self.db_conn = MongoDbDataSource(self.connection_name)
+        self.database = self.db_conn.database
         # TODO Réimplémenter la partie sur les settings
         mh_settings = {}
         self.dryrun = kwargs['dryrun'] if 'dryrun' in kwargs else mh_settings['dryrun']
@@ -34,8 +39,35 @@ class MongoDbMigrationHandler(GenericMigrationHandler):
     # @param new_state dict|None : dict with field name as key and field value as value. Represents the new state. None means it's a component deletion.
     # @throw MigrationHandlerChangeError if the change was refused
     def register_change(self, em, uid, initial_state, new_state):
-        pass
-
+        if isinstance(em.classes(uid), EmClass):
+            collection_name = utils.object_collection_name(em.classes(uid).display_name)
+            if initial_state is None:
+                self._create_collection(collection_name)
+            elif new_state is None:
+                self._delete_collection(collection_name)
 
     def _create_default_collections(self, drop_if_exist=False):
-        pass
+        if_exists = 'drop' if drop_if_exist else 'nothing'
+        # Object collection
+        collection_name = utils.common_collections['object']
+        self._create_collection(collection_name, if_exists=if_exists)
+        # TODO triggers ?
+        object_collection_name = collection_name
+
+        # TODO collections de relations
+        # TODO clés étrangères
+
+    def _create_collection(self, collection_name, if_exists='nothing'):
+        if if_exists == 'drop':
+            if collection_name in self.database.collection_names():
+                self.database[collection_name].drop()
+        else:
+            if collection_name not in self.database.collection_names():
+                self.database.create_collection(collection_name)
+
+        # TODO Relational fields
+
+    def _delete_collection(self, collection_name):
+        # TODO : delete the triggers ?
+        if collection_name in self.database.collection_names():
+            self.database[collection_name].drop()
diff --git a/lodel/datasource/mongodb/utils.py b/lodel/datasource/mongodb/utils.py
index f67c3ee..dac6310 100644
--- a/lodel/datasource/mongodb/utils.py
+++ b/lodel/datasource/mongodb/utils.py
@@ -2,6 +2,10 @@
 
 import pymongo
 
+common_collections = {
+    'object': 'object'
+}
+
 collection_prefix = {
     'relation': 'rel_',
     'collection': 'class_'
@@ -30,6 +34,7 @@ MONGODB_SORT_OPERATORS_MAP = {
     'DESC': -1
 }
 
+
 ## @brief Returns a collection name given a Emclass name
 # @param class_name str : The class name
 # @return str