def _prepare(self, model):
if self.order_with_respect_to:
self.order_with_respect_to = self.get_field(
self.order_with_respect_to)
self.ordering = ('_order', )
model.add_to_class('_order', OrderWrt())
else:
self.order_with_respect_to = None
if self.pk is None:
if self.parents:
# Promote the first parent link in lieu of adding yet another
# field.
field = next(six.itervalues(self.parents))
# Look for a local field with the same name as the
# first parent link. If a local field has already been
# created, use it instead of promoting the parent
already_created = [
fld for fld in self.local_fields if fld.name == field.name
]
if already_created:
field = already_created[0]
field.primary_key = True
self.setup_pk(field)
else:
auto = AutoField(verbose_name='ID',
primary_key=True,
auto_created=True)
model.add_to_class('id', auto)
def _prepare(self, model):
if self.order_with_respect_to:
# The app registry will not be ready at this point, so we cannot
# use get_field().
query = self.order_with_respect_to
try:
self.order_with_respect_to = next(
f for f in self._get_fields(reverse=False)
if f.name == query or f.attname == query
)
except StopIteration:
raise FieldDoesNotExist("%s has no field named '%s'" % (self.object_name, query))
self.ordering = ('_order',)
if not any(isinstance(field, OrderWrt) for field in model._meta.local_fields):
model.add_to_class('_order', OrderWrt())
else:
self.order_with_respect_to = None
if self.pk is None:
if self.parents:
# Promote the first parent link in lieu of adding yet another
# field.
field = next(iter(self.parents.values()))
# Look for a local field with the same name as the
# first parent link. If a local field has already been
# created, use it instead of promoting the parent
already_created = [fld for fld in self.local_fields if fld.name == field.name]
if already_created:
field = already_created[0]
field.primary_key = True
self.setup_pk(field)
else:
auto = AutoField(verbose_name='ID', primary_key=True, auto_created=True)
model.add_to_class('id', auto)
def _prepare(self, model):
# 排序的属性
if self.order_with_respect_to:
self.order_with_respect_to = self.get_field(self.order_with_respect_to)
self.ordering = ('_order',)
model.add_to_class('_order', OrderWrt())
else:
self.order_with_respect_to = None
if self.pk is None:
if self.parents:
# Promote 促进, 提升 the first parent link in lieu of adding yet another
# field.
field = next(six.itervalues(self.parents))
# Look for a local field with the same name as the
# first parent link. If a local field has already been
# created, use it instead of promoting the parent
already_created = [fld for fld in self.local_fields if fld.name == field.name]
if already_created:
field = already_created[0]
field.primary_key = True
self.setup_pk(field)
else:
auto = AutoField(verbose_name='ID', primary_key=True,
auto_created=True)
model.add_to_class('id', auto)
# 如果两个属性同时关联两个外部表, 比如两个外键的时候, 需要创建一个集合.
# Determine any sets of fields that are pointing to the same targets
# (e.g. two ForeignKeys to the same remote model). The query
# construction code needs to know this. At the end of this,
# self.duplicate_targets will map each duplicate field column to the
# columns it duplicates.
collections = {}
for column, target in six.iteritems(self.duplicate_targets):
try:
collections[target].add(column)
except KeyError:
collections[target] = set([column])
self.duplicate_targets = {}
for elt in six.itervalues(collections):
if len(elt) == 1:
continue
for column in elt:
# elt_set - set([column])
self.duplicate_targets[column] = elt.difference(set([column]))
def init_name_map(self):
"""
Initialises the field name -> field object mapping.
"""
cache = {}
# We intentionally handle related m2m objects first so that symmetrical
# m2m accessor names can be overridden, if necessary.
for f, model in self.get_all_related_m2m_objects_with_model():
cache[f.field.related_query_name()] = (f, model, False, True)
for f, model in self.get_all_related_objects_with_model():
cache[f.field.related_query_name()] = (f, model, False, False)
for f, model in self.get_m2m_with_model():
cache[f.name] = (f, model, True, True)
for f, model in self.get_fields_with_model():
cache[f.name] = (f, model, True, False)
if self.order_with_respect_to:
cache['_order'] = OrderWrt(), None, True, False
if app_cache_ready():
self._name_map = cache
return cache
def _prepare(self, model):
if self.order_with_respect_to:
self.order_with_respect_to = self.get_field(
self.order_with_respect_to)
self.ordering = ('_order', )
model.add_to_class('_order', OrderWrt())
else:
self.order_with_respect_to = None
if self.pk is None:
if self.parents:
# Promote the first parent link in lieu of adding yet another
# field.
field = self.parents.value_for_index(0)
field.primary_key = True
self.setup_pk(field)
else:
auto = AutoField(verbose_name='ID',
primary_key=True,
auto_created=True)
model.add_to_class('id', auto)
# Determine any sets of fields that are pointing to the same targets
# (e.g. two ForeignKeys to the same remote model). The query
# construction code needs to know this. At the end of this,
# self.duplicate_targets will map each duplicate field column to the
# columns it duplicates.
collections = {}
for column, target in self.duplicate_targets.iteritems():
try:
collections[target].add(column)
except KeyError:
collections[target] = set([column])
self.duplicate_targets = {}
for elt in collections.itervalues():
if len(elt) == 1:
continue
for column in elt:
self.duplicate_targets[column] = elt.difference(set([column]))
