ReferenceField now store ObjectId's by default rather than DBRef (#290)

docs/changelog.rst

@@ -4,6 +4,7 @@ Changelog
 
 Changes in 0.8.X
 ================
+- ReferenceField now store ObjectId's by default rather than DBRef (#290)
 - Added ImageField support for inline replacements (#86)
 - Added SequenceField.set_next_value(value) helper (#159)
 - Updated .only() behaviour - now like exclude it is chainable (#202)

docs/upgrade.rst

@@ -76,6 +76,35 @@ the case and the data is set only in the ``document._data`` dictionary: ::
       File "<stdin>", line 1, in <module>
     AttributeError: 'Animal' object has no attribute 'size'
 
+ReferenceField
+--------------
+
+ReferenceFields now store ObjectId's by default - this is more efficient than
+DBRefs as we already know what Document types they reference.
+
+    # Old code
+    class Animal(Document):
+        name = ReferenceField('self')
+
+    # New code to keep dbrefs
+    class Animal(Document):
+        name = ReferenceField('self', dbref=True)
+
+To migrate all the references you need to touch each object and mark it as dirty
+eg::
+
+    # Doc definition
+    class Person(Document):
+        name = StringField()
+        parent = ReferenceField('self')
+        friends = ListField(ReferenceField('self'))
+
+    # Mark all ReferenceFields as dirty and save
+    for p in Person.objects:
+        p._mark_as_dirty('parent')
+        p._mark_as_dirty('friends')
+        p.save()
+
 Querysets
 =========
 

mongoengine/fields.py

@@ -772,7 +772,7 @@ class ReferenceField(BaseField):
     .. versionchanged:: 0.5 added `reverse_delete_rule`
     """
 
-    def __init__(self, document_type, dbref=None,
+    def __init__(self, document_type, dbref=False,
                  reverse_delete_rule=DO_NOTHING, **kwargs):
         """Initialises the Reference Field.
 
@@ -786,12 +786,7 @@ class ReferenceField(BaseField):
                 self.error('Argument to ReferenceField constructor must be a '
                            'document class or a string')
 
-        if dbref is None:
-            msg = ("ReferenceFields will default to using ObjectId "
-                   "in 0.8, set DBRef=True if this isn't desired")
-            warnings.warn(msg, FutureWarning)
-
-        self.dbref = dbref if dbref is not None else True  # To change in 0.8
+        self.dbref = dbref
         self.document_type_obj = document_type
         self.reverse_delete_rule = reverse_delete_rule
         super(ReferenceField, self).__init__(**kwargs)

tests/all_warnings/__init__.py

@@ -30,28 +30,6 @@ class AllWarnings(unittest.TestCase):
         # restore default handling of warnings
         warnings.showwarning = self.showwarning_default
 
-    def test_dbref_reference_field_future_warning(self):
-
-        class Person(Document):
-            name = StringField()
-            parent = ReferenceField('self')
-
-        Person.drop_collection()
-
-        p1 = Person()
-        p1.parent = None
-        p1.save()
-
-        p2 = Person(name="Wilson Jr")
-        p2.parent = p1
-        p2.save(cascade=False)
-
-        self.assertTrue(len(self.warning_list) > 0)
-        warning = self.warning_list[0]
-        self.assertEqual(FutureWarning, warning["category"])
-        self.assertTrue("ReferenceFields will default to using ObjectId"
-                        in str(warning["message"]))
-
     def test_document_save_cascade_future_warning(self):
 
         class Person(Document):

tests/migration/__init__.py

@@ -1,3 +1,5 @@
+from convert_to_new_inheritance_model import *
+from refrencefield_dbref_to_object_id import *
 from turn_off_inheritance import *
 
 if __name__ == '__main__':

tests/migration/convert_to_new_inheritance_model.py

@@ -38,7 +38,7 @@ class ConvertToNewInheritanceModel(unittest.TestCase):
 
         # 3. Confirm extra data is removed
         count = collection.find({'_types': {"$exists": True}}).count()
-        assert count == 0
+        self.assertEqual(0, count)
 
         # 4. Remove indexes
         info = collection.index_information()

tests/migration/refrencefield_dbref_to_object_id.py

@@ -0,0 +1,52 @@
+# -*- coding: utf-8 -*-
+import unittest
+
+from mongoengine import Document, connect
+from mongoengine.connection import get_db
+from mongoengine.fields import StringField, ReferenceField, ListField
+
+__all__ = ('ConvertToObjectIdsModel', )
+
+
+class ConvertToObjectIdsModel(unittest.TestCase):
+
+    def setUp(self):
+        connect(db='mongoenginetest')
+        self.db = get_db()
+
+    def test_how_to_convert_to_object_id_reference_fields(self):
+        """Demonstrates migrating from 0.7 to 0.8
+        """
+
+        # 1. Old definition - using dbrefs
+        class Person(Document):
+            name = StringField()
+            parent = ReferenceField('self', dbref=True)
+            friends = ListField(ReferenceField('self', dbref=True))
+
+        Person.drop_collection()
+
+        p1 = Person(name="Wilson", parent=None).save()
+        f1 = Person(name="John", parent=None).save()
+        f2 = Person(name="Paul", parent=None).save()
+        f3 = Person(name="George", parent=None).save()
+        f4 = Person(name="Ringo", parent=None).save()
+        Person(name="Wilson Jr", parent=p1, friends=[f1, f2, f3, f4]).save()
+
+        # 2. Start the migration by changing the schema
+        # Change ReferenceField as now dbref defaults to False
+        class Person(Document):
+            name = StringField()
+            parent = ReferenceField('self')
+            friends = ListField(ReferenceField('self'))
+
+        # 3. Loop all the objects and mark parent as changed
+        for p in Person.objects:
+            p._mark_as_changed('parent')
+            p._mark_as_changed('friends')
+            p.save()
+
+        # 4. Confirmation of the fix!
+        wilson = Person.objects(name="Wilson Jr").as_pymongo()[0]
+        self.assertEqual(p1.id, wilson['parent'])
+        self.assertEqual([f1.id, f2.id, f3.id, f4.id], wilson['friends'])

tests/test_signals.py

@@ -72,6 +72,7 @@ class SignalTests(unittest.TestCase):
                 else:
                     signal_output.append('Not loaded')
         self.Author = Author
+        Author.drop_collection()
 
         class Another(Document):
             name = StringField()
@@ -110,6 +111,7 @@ class SignalTests(unittest.TestCase):
                 signal_output.append('post_delete Another signal, %s' % document)
 
         self.Another = Another
+        Another.drop_collection()
 
         class ExplicitId(Document):
             id = IntField(primary_key=True)
@@ -123,7 +125,8 @@ class SignalTests(unittest.TestCase):
                         signal_output.append('Is updated')
 
         self.ExplicitId = ExplicitId
-        self.ExplicitId.objects.delete()
+        ExplicitId.drop_collection()
+
         # Save up the number of connected signals so that we can check at the
         # end that all the signals we register get properly unregistered
         self.pre_signals = (