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Tweaked SequenceField so that it doesn't increment on creation.

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[refs #238]
This commit is contained in:
Ross Lawley 2011-07-19 16:51:26 +01:00
parent 5eb895b952
commit 5834fa840c
5 changed files with 95 additions and 31 deletions
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1
AUTHORS
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@ -4,3 +4,4 @@ Deepak Thukral <iapain@yahoo.com>
Florian Schlachter <flori@n-schlachter.de>
Steve Challis <steve@stevechallis.com>
Ross Lawley <ross.lawley@gmail.com>
Wilson Júnior <wilsonpjunior@gmail.com>

1
docs/changelog.rst
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@ -5,6 +5,7 @@ Changelog
Changes in dev
==============
- Added SequenceField - for creating sequential counters
- Added update() convenience method to a document
- Added cascading saves - so changes to Referenced documents are saved on .save()
- Added select_related() support

9
mongoengine/base.py
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@ -587,7 +587,8 @@ class BaseDocument(object):
# Set any get_fieldname_display methods
self.__set_field_display()
# Flag initialised
self._initialised = True
signals.post_init.send(self.__class__, document=self)
def validate(self):
@ -773,13 +774,13 @@ class BaseDocument(object):
d = getattr(d, real_path)
else:
d = d.get(p)
if hasattr(d, '_fields'):
field_name = d._reverse_db_field_map.get(db_field_name,
db_field_name)
default = d._fields[field_name].default
if default is not None:
if callable(default):
default = default()

36
mongoengine/fields.py
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@ -880,30 +880,46 @@ class GeoPointField(BaseField):
class SequenceField(IntField):
"""Provides a sequental counter.
..note:: Although traditional databases often use increasing sequence
numbers for primary keys. In MongoDB, the preferred approach is to
use Object IDs instead. The concept is that in a very large
cluster of machines, it is easier to create an object ID than have
global, uniformly increasing sequence numbers.
.. versionadded:: 0.5
"""
def __init__(self, collection_name=None, *args, **kwargs):
self.collection_name = collection_name or 'mongoengine.counters'
return super(SequenceField, self).__init__(*args, **kwargs)
def generate_new_value(self):
"""
Generate and Increment counter
Generate and Increment the counter
"""
sequence_id = "{0}.{1}".format(self.owner_document._get_collection_name(),
self.name)
collection = _get_db()['mongoengine.counters']
collection = _get_db()[self.collection_name]
counter = collection.find_and_modify(query={"_id": sequence_id},
update={"$inc" : {"next": 1}},
update={"$inc": {"next": 1}},
new=True,
upsert=True)
return counter['next']
def __get__(self, instance, owner):
if not instance._data:
return
if instance is None:
return self
if not instance._data:
return
value = instance._data.get(self.name)
if not value:
if not value and instance._initialised:
value = self.generate_new_value()
instance._data[self.name] = value
return value
def to_python(self, value):
if value is None:
value = self.generate_new_value()
return value

79
tests/fields.py
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@ -1379,20 +1379,7 @@ class FieldTest(unittest.TestCase):
self.assertEqual(d2.data, {})
self.assertEqual(d2.data2, {})
def test_sequence_field(self):
class Person(Document):
id = SequenceField(primary_key=True)
self.db['mongoengine.counters'].drop()
Person.drop_collection()
p = Person()
p.save()
p = Person.objects.first()
self.assertEqual(p.id, 1)
def test_multiple_sequence_field(self):
class Person(Document):
id = SequenceField(primary_key=True)
name = StringField()
@ -1404,18 +1391,76 @@ class FieldTest(unittest.TestCase):
p = Person(name="Person %s" % x)
p.save()
c = self.db['mongoengine.counters'].find_one({'_id': 'person.id'})
self.assertEqual(c['next'], 10)
ids = [i.id for i in Person.objects]
self.assertEqual(ids, range(1, 11))
c = self.db['mongoengine.counters'].find_one({'_id': 'person.id'})
self.assertEqual(c['next'], 10)
def test_multiple_sequence_fields(self):
class Person(Document):
id = SequenceField(primary_key=True)
counter = SequenceField()
name = StringField()
self.db['mongoengine.counters'].drop()
Person.drop_collection()
for x in xrange(10):
p = Person(name="Person %s" % x)
p.save()
ids = [i.id for i in Person.objects]
self.assertEqual(ids, range(1, 21))
c = self.db['mongoengine.counters'].find_one({'_id': 'person.id'})
self.assertEqual(c['next'], 10)
ids = [i.id for i in Person.objects]
self.assertEqual(ids, range(1, 11))
counters = [i.counter for i in Person.objects]
self.assertEqual(counters, range(1, 11))
c = self.db['mongoengine.counters'].find_one({'_id': 'person.id'})
self.assertEqual(c['next'], 10)
def test_multiple_sequence_fields_on_docs(self):
class Animal(Document):
id = SequenceField(primary_key=True)
class Person(Document):
id = SequenceField(primary_key=True)
self.db['mongoengine.counters'].drop()
Animal.drop_collection()
Person.drop_collection()
for x in xrange(10):
a = Animal(name="Animal %s" % x)
a.save()
p = Person(name="Person %s" % x)
p.save()
c = self.db['mongoengine.counters'].find_one({'_id': 'person.id'})
self.assertEqual(c['next'], 10)
c = self.db['mongoengine.counters'].find_one({'_id': 'animal.id'})
self.assertEqual(c['next'], 10)
ids = [i.id for i in Person.objects]
self.assertEqual(ids, range(1, 11))
id = [i.id for i in Animal.objects]
self.assertEqual(id, range(1, 11))
c = self.db['mongoengine.counters'].find_one({'_id': 'person.id'})
self.assertEqual(c['next'], 10)
c = self.db['mongoengine.counters'].find_one({'_id': 'animal.id'})
self.assertEqual(c['next'], 10)
counter = self.db['mongoengine.counters'].find_one({'_id': 'person.id'})
self.assertEqual(counter['next'], 20)
if __name__ == '__main__':
unittest.main()