我们从Python开源项目中，提取了以下21个代码示例，用于说明如何使用django.db.models.deletion.CASCADE。
def __init__(self, to, from_fields, to_fields, swappable=True, **kwargs): self.from_fields = from_fields self.to_fields = to_fields self.swappable = swappable if 'rel' not in kwargs: kwargs['rel'] = ForeignObjectRel( self, to, related_name=kwargs.pop('related_name', None), related_query_name=kwargs.pop('related_query_name', None), limit_choices_to=kwargs.pop('limit_choices_to', None), parent_link=kwargs.pop('parent_link', False), on_delete=kwargs.pop('on_delete', CASCADE), ) kwargs['verbose_name'] = kwargs.get('verbose_name', None) super(ForeignObject, self).__init__(**kwargs)
def __init__(self, to, on_delete=None, to_field=None, **kwargs): kwargs['unique'] = True if on_delete is None: warnings.warn( "on_delete will be a required arg for %s in Django 2.0. Set " "it to models.CASCADE on models and in existing migrations " "if you want to maintain the current default behavior. " "See https://docs.djangoproject.com/en/%s/ref/models/fields/" "#django.db.models.ForeignKey.on_delete" % ( self.__class__.__name__, get_docs_version(), ), RemovedInDjango20Warning, 2) on_delete = CASCADE elif not callable(on_delete): warnings.warn( "The signature for {0} will change in Django 2.0. " "Pass to_field='{1}' as a kwarg instead of as an arg.".format( self.__class__.__name__, on_delete, ), RemovedInDjango20Warning, 2) to_field = on_delete on_delete = CASCADE # Avoid warning in superclass super(OneToOneField, self).__init__(to, on_delete, to_field=to_field, **kwargs)
def deconstruct(self): name, path, args, kwargs = super(ForeignObject, self).deconstruct() kwargs['from_fields'] = self.from_fields kwargs['to_fields'] = self.to_fields if self.rel.related_name is not None: kwargs['related_name'] = self.rel.related_name if self.rel.related_query_name is not None: kwargs['related_query_name'] = self.rel.related_query_name if self.rel.on_delete != CASCADE: kwargs['on_delete'] = self.rel.on_delete if self.rel.parent_link: kwargs['parent_link'] = self.rel.parent_link # Work out string form of "to" if isinstance(self.rel.to, six.string_types): kwargs['to'] = self.rel.to else: kwargs['to'] = "%s.%s" % (self.rel.to._meta.app_label, self.rel.to._meta.object_name) # If swappable is True, then see if we're actually pointing to the target # of a swap. swappable_setting = self.swappable_setting if swappable_setting is not None: # If it's already a settings reference, error if hasattr(kwargs['to'], "setting_name"): if kwargs['to'].setting_name != swappable_setting: raise ValueError( "Cannot deconstruct a ForeignKey pointing to a model " "that is swapped in place of more than one model (%s and %s)" % (kwargs['to'].setting_name, swappable_setting) ) # Set it from django.db.migrations.writer import SettingsReference kwargs['to'] = SettingsReference( kwargs['to'], swappable_setting, ) return name, path, args, kwargs
def __init__(self, to, to_field=None, rel_class=ManyToOneRel, db_constraint=True, **kwargs): try: to._meta.model_name except AttributeError: # to._meta doesn't exist, so it must be RECURSIVE_RELATIONSHIP_CONSTANT assert isinstance(to, six.string_types), ( "%s(%r) is invalid. First parameter to ForeignKey must be " "either a model, a model name, or the string %r" % ( self.__class__.__name__, to, RECURSIVE_RELATIONSHIP_CONSTANT, ) ) else: # For backwards compatibility purposes, we need to *try* and set # the to_field during FK construction. It won't be guaranteed to # be correct until contribute_to_class is called. Refs #12190. to_field = to_field or (to._meta.pk and to._meta.pk.name) if 'db_index' not in kwargs: kwargs['db_index'] = True self.db_constraint = db_constraint kwargs['rel'] = rel_class( self, to, to_field, related_name=kwargs.pop('related_name', None), related_query_name=kwargs.pop('related_query_name', None), limit_choices_to=kwargs.pop('limit_choices_to', None), parent_link=kwargs.pop('parent_link', False), on_delete=kwargs.pop('on_delete', CASCADE), ) super(ForeignKey, self).__init__(to, ['self'], [to_field], **kwargs)
def __init__(self, to, on_delete=None, related_name=None, related_query_name=None, limit_choices_to=None, parent_link=False, to_field=None, db_constraint=True, **kwargs): try: to._meta.model_name except AttributeError: assert isinstance(to, six.string_types), ( "%s(%r) is invalid. First parameter to ForeignKey must be " "either a model, a model name, or the string %r" % ( self.__class__.__name__, to, RECURSIVE_RELATIONSHIP_CONSTANT, ) ) else: # For backwards compatibility purposes, we need to *try* and set # the to_field during FK construction. It won't be guaranteed to # be correct until contribute_to_class is called. Refs #12190. to_field = to_field or (to._meta.pk and to._meta.pk.name) if on_delete is None: warnings.warn( "on_delete will be a required arg for %s in Django 2.0. Set " "it to models.CASCADE on models and in existing migrations " "if you want to maintain the current default behavior. " "See https://docs.djangoproject.com/en/%s/ref/models/fields/" "#django.db.models.ForeignKey.on_delete" % ( self.__class__.__name__, get_docs_version(), ), RemovedInDjango20Warning, 2) on_delete = CASCADE elif not callable(on_delete): warnings.warn( "The signature for {0} will change in Django 2.0. " "Pass to_field='{1}' as a kwarg instead of as an arg.".format( self.__class__.__name__, on_delete, ), RemovedInDjango20Warning, 2) on_delete, to_field = to_field, on_delete kwargs['rel'] = self.rel_class( self, to, to_field, related_name=related_name, related_query_name=related_query_name, limit_choices_to=limit_choices_to, parent_link=parent_link, on_delete=on_delete, ) kwargs['db_index'] = kwargs.get('db_index', True) super(ForeignKey, self).__init__( to, on_delete, from_fields=['self'], to_fields=[to_field], **kwargs) self.db_constraint = db_constraint
def create_many_to_many_intermediary_model(field, klass): from django.db import models def set_managed(model, related, through): through._meta.managed = model._meta.managed or related._meta.managed to_model = resolve_relation(klass, field.remote_field.model) name = '%s_%s' % (klass._meta.object_name, field.name) lazy_related_operation(set_managed, klass, to_model, name) to = make_model_tuple(to_model)[1] from_ = klass._meta.model_name if to == from_: to = 'to_%s' % to from_ = 'from_%s' % from_ meta = type(str('Meta'), (object,), { 'db_table': field._get_m2m_db_table(klass._meta), 'auto_created': klass, 'app_label': klass._meta.app_label, 'db_tablespace': klass._meta.db_tablespace, 'unique_together': (from_, to), 'verbose_name': '%(from)s-%(to)s relationship' % {'from': from_, 'to': to}, 'verbose_name_plural': '%(from)s-%(to)s relationships' % {'from': from_, 'to': to}, 'apps': field.model._meta.apps, }) # Construct and return the new class. return type(str(name), (models.Model,), { 'Meta': meta, '__module__': klass.__module__, from_: models.ForeignKey( klass, related_name='%s+' % name, db_tablespace=field.db_tablespace, db_constraint=field.remote_field.db_constraint, on_delete=CASCADE, ), to: models.ForeignKey( to_model, related_name='%s+' % name, db_tablespace=field.db_tablespace, db_constraint=field.remote_field.db_constraint, on_delete=CASCADE, ) })
def create_many_to_many_intermediary_model(field, klass): from django.db import models def set_managed(model, related, through): through._meta.managed = model._meta.managed or related._meta.managed to_model = resolve_relation(klass, field.remote_field.model) name = '%s_%s' % (klass._meta.object_name, field.name) lazy_related_operation(set_managed, klass, to_model, name) to = make_model_tuple(to_model)[1] from_ = klass._meta.model_name if to == from_: to = 'to_%s' % to from_ = 'from_%s' % from_ meta = type(str('Meta'), (object,), { 'db_table': field._get_m2m_db_table(klass._meta), 'auto_created': klass, 'app_label': klass._meta.app_label, 'db_tablespace': klass._meta.db_tablespace, 'unique_together': (from_, to), 'verbose_name': _('%(from)s-%(to)s relationship') % {'from': from_, 'to': to}, 'verbose_name_plural': _('%(from)s-%(to)s relationships') % {'from': from_, 'to': to}, 'apps': field.model._meta.apps, }) # Construct and return the new class. return type(str(name), (models.Model,), { 'Meta': meta, '__module__': klass.__module__, from_: models.ForeignKey( klass, related_name='%s+' % name, db_tablespace=field.db_tablespace, db_constraint=field.remote_field.db_constraint, on_delete=CASCADE, ), to: models.ForeignKey( to_model, related_name='%s+' % name, db_tablespace=field.db_tablespace, db_constraint=field.remote_field.db_constraint, on_delete=CASCADE, ) })
