def populate_foreign_key_caches(model, objects_to_populate, fields=None):
"""
Populates caches for the given related Model in instances of objects
which have a ForeignKey relationship to it, specified as a list of
(object list, related attribute name list) two-tuples.
If a list of field names is given, only the given fields will be
looked up and related object caches will be populated with a dict of
the specified fields. Otherwise, complete model instances will be
retrieved.
"""
# Get all related object ids for the appropriate fields
related_object_ids = []
for objects, attrs in objects_to_populate:
related_object_ids.append(tuple(tuple(getattr(obj, '%s_id' % attr)
for attr in attrs)
for obj in objects))
unique_ids = tuple(set(pk for pk in flatten(related_object_ids) if pk))
related_objects = fetch_model_dict(model, unique_ids, fields)
# Fill related object caches
for (objects, attrs), related_ids in itertools.izip(objects_to_populate,
related_object_ids):
for obj, related_ids_for_obj in itertools.izip(objects,
related_ids):
for attr, related_object in itertools.izip(attrs, (related_objects.get(pk, None)
for pk in related_ids_for_obj)):
setattr(obj, '_%s_cache' % attr, related_object)
def populate_foreign_key_caches(model, objects_to_populate, fields=None):
"""
Populates caches for the given related Model in instances of objects
which have a ForeignKey relationship to it, specified as a list of
(object list, related attribute name list) two-tuples.
If a list of field names is given, only the given fields will be
looked up and related object caches will be populated with a dict of
the specified fields. Otherwise, complete model instances will be
retrieved.
"""
# Get all related object ids for the appropriate fields
related_object_ids = []
for objects, attrs in objects_to_populate:
related_object_ids.append(
tuple(
tuple(getattr(obj, '%s_id' % attr) for attr in attrs)
for obj in objects))
unique_ids = tuple(set(pk for pk in flatten(related_object_ids) if pk))
related_objects = fetch_model_dict(model, unique_ids, fields)
# Fill related object caches
for (objects,
attrs), related_ids in itertools.izip(objects_to_populate,
related_object_ids):
for obj, related_ids_for_obj in itertools.izip(objects, related_ids):
for attr, related_object in itertools.izip(
attrs,
(related_objects.get(pk, None) for pk in related_ids_for_obj)):
setattr(obj, '_%s_cache' % attr, related_object)
def update_reputation(manager, changes):
"""
Updates User reputation scores where changes are specified as
two-tuples of (User id, reputation score change), ensuring that
a User's reputation score can't go below 1.
"""
change_count = len(changes)
cursor = connection.cursor()
cursor.execute(
'UPDATE auth_user SET reputation = CASE %s ELSE reputation END '
'WHERE id IN (%s)' %
(' '.join(['WHEN id = %s THEN MAX(1, reputation + %s)'] *
change_count), ','.join(['%s'] * change_count)),
flatten(changes) + [c[0] for c in changes])
transaction.commit_unless_managed()
def update_reputation(manager, changes):
"""
Updates User reputation scores where changes are specified as
two-tuples of (User id, reputation score change), ensuring that
a User's reputation score can't go below 1.
"""
change_count = len(changes)
cursor = connection.cursor()
cursor.execute(
'UPDATE auth_user SET reputation = CASE %s ELSE reputation END '
'WHERE id IN (%s)' % (
' '.join(['WHEN id = %s THEN MAX(1, reputation + %s)'] * change_count),
','.join(['%s'] * change_count)),
flatten(changes) + [c[0] for c in changes])
transaction.commit_unless_managed()
