我们从Python开源项目中，提取了以下24个代码示例，用于说明如何使用django.db.models.NOT_PROVIDED。
def compare_fields(instance, new_data, ignore_fields): """Compare a model instance to a new dict; return True if they match""" for field in instance._meta.fields: if field.name in ignore_fields: # ignored fields continue current_value = getattr(instance, field.name) if field.name not in new_data: # no value provided, check if the current value is the default default = field.default if field.default is not NOT_PROVIDED else None if current_value == default: continue else: return False if current_value != new_data[field.name]: return False return True
def contribute_to_class(self, cls, name, private_only=False, virtual_only=NOT_PROVIDED): super().contribute_to_class(cls, name, private_only, virtual_only) allowed_tags = self._allowed_tags def html_FIELD(self, tags=None): if tags is None: if isinstance(allowed_tags, str): tags = getattr(self, allowed_tags) else: tags = allowed_tags if tags is None: raise TypeError('Cannot call html_{0} without a tags argument if no default was set on field {0} creation'.format(name)) if callable(tags): tags = tags() if not isinstance(tags, list): tags = list(tags) return sanitize_html(getattr(self, name), tags) setattr(cls, 'html_{}'.format(name), html_FIELD)
def operation_is_safe(operation): if not isinstance(operation, SAFE_OPERATIONS): return False elif isinstance(operation, (operations.AddField, operations.AlterField)): if operation.field.null is False or operation.field.default is not NOT_PROVIDED: return False return True
def add_field(self, model, field): super(DatabaseSchemaEditor, self).add_field(model, field) # Simulate the effect of a one-off default. # field.default may be unhashable, so a set isn't used for "in" check. if self.skip_default(field) and field.default not in (None, NOT_PROVIDED): effective_default = self.effective_default(field) self.execute('UPDATE %(table)s SET %(column)s = %%s' % { 'table': self.quote_name(model._meta.db_table), 'column': self.quote_name(field.column), }, [effective_default])
def add_field(self, model, field): super(DatabaseSchemaEditor, self).add_field(model, field) # Simulate the effect of a one-off default. if (self.skip_default(field) and field.default not in (None, NOT_PROVIDED)): effective_default = self.effective_default(field) self.execute('UPDATE %(table)s SET %(column)s = %%s' % { 'table': self.quote_name(model._meta.db_table), 'column': self.quote_name(field.column), }, [effective_default])
def add_field(self, model, field): super(DatabaseSchemaEditor, self).add_field(model, field) # Simulate the effect of a one-off default. if self.skip_default(field) and field.default not in {None, NOT_PROVIDED}: effective_default = self.effective_default(field) self.execute('UPDATE %(table)s SET %(column)s = %%s' % { 'table': self.quote_name(model._meta.db_table), 'column': self.quote_name(field.column), }, [effective_default])
def json_get_cached_first_disk_image(self): if self._first_disk_image is NOT_PROVIDED: self._first_disk_image = self.json_get_first_disk_image() return self._first_disk_image
def get_field_meta(self, field: models.Field) -> OrderedDict: d = OrderedDict() sentinel = object() for attr in self.attr_list: val = getattr(field, attr, sentinel) if val is sentinel: continue if attr in ['max_length']: if val is None: continue if attr in ['verbose_name']: val = force_text(val) d[attr] = val d['type'] = field.get_internal_type() d['required'] = self.is_required(field) if field.default != models.NOT_PROVIDED: if callable(field.default): d['default'] = field.default() else: d['default'] = field.default if hasattr(field, 'choices') and field.choices: d['choices'] = list(self.format_choices(field)) if field.related_model: if field.name not in self.no_data: user_url_getter = getattr(self, 'get_%s_dataset_url' % field.name.lower(), None) if callable(user_url_getter): d['data'] = user_url_getter(field, self.obj) elif field.name in self.dataset_urls: d['data'] = force_text(self.dataset_urls[field.name]) else: d['data'] = self.get_field_related_data(field) data_update = self.update_fields.get(field.name, {}) d.update(data_update) return d # noinspection PyMethodMayBeStatic,PyUnusedLocal
def generate_altered_fields(self): """ Fields that have been altered. """ for app_label, model_name, field_name in sorted(self.old_field_keys.intersection(self.new_field_keys)): # Did the field change? old_model_name = self.renamed_models.get((app_label, model_name), model_name) old_field_name = self.renamed_fields.get((app_label, model_name, field_name), field_name) old_field = self.old_apps.get_model(app_label, old_model_name)._meta.get_field(old_field_name) new_field = self.new_apps.get_model(app_label, model_name)._meta.get_field(field_name) # Implement any model renames on relations; these are handled by RenameModel # so we need to exclude them from the comparison if hasattr(new_field, "remote_field") and getattr(new_field.remote_field, "model", None): rename_key = ( new_field.remote_field.model._meta.app_label, new_field.remote_field.model._meta.model_name, ) if rename_key in self.renamed_models: new_field.remote_field.model = old_field.remote_field.model old_field_dec = self.deep_deconstruct(old_field) new_field_dec = self.deep_deconstruct(new_field) if old_field_dec != new_field_dec: both_m2m = ( isinstance(old_field, models.ManyToManyField) and isinstance(new_field, models.ManyToManyField) ) neither_m2m = ( not isinstance(old_field, models.ManyToManyField) and not isinstance(new_field, models.ManyToManyField) ) if both_m2m or neither_m2m: # Either both fields are m2m or neither is preserve_default = True if (old_field.null and not new_field.null and not new_field.has_default() and not isinstance(new_field, models.ManyToManyField)): field = new_field.clone() new_default = self.questioner.ask_not_null_alteration(field_name, model_name) if new_default is not models.NOT_PROVIDED: field.default = new_default preserve_default = False else: field = new_field self.add_operation( app_label, operations.AlterField( model_name=model_name, name=field_name, field=field, preserve_default=preserve_default, ) ) else: # We cannot alter between m2m and concrete fields self._generate_removed_field(app_label, model_name, field_name) self._generate_added_field(app_label, model_name, field_name)
def generate_altered_fields(self): """ Fields that have been altered. """ for app_label, model_name, field_name in sorted(self.old_field_keys.intersection(self.new_field_keys)): # Did the field change? old_model_name = self.renamed_models.get((app_label, model_name), model_name) old_field_name = self.renamed_fields.get((app_label, model_name, field_name), field_name) old_field = self.old_apps.get_model(app_label, old_model_name)._meta.get_field(old_field_name) new_field = self.new_apps.get_model(app_label, model_name)._meta.get_field(field_name) # Implement any model renames on relations; these are handled by RenameModel # so we need to exclude them from the comparison if hasattr(new_field, "remote_field") and getattr(new_field.remote_field, "model", None): rename_key = ( new_field.remote_field.model._meta.app_label, new_field.remote_field.model._meta.model_name, ) if rename_key in self.renamed_models: new_field.remote_field.model = old_field.remote_field.model if hasattr(new_field, "remote_field") and getattr(new_field.remote_field, "through", None): rename_key = ( new_field.remote_field.through._meta.app_label, new_field.remote_field.through._meta.model_name, ) if rename_key in self.renamed_models: new_field.remote_field.through = old_field.remote_field.through old_field_dec = self.deep_deconstruct(old_field) new_field_dec = self.deep_deconstruct(new_field) if old_field_dec != new_field_dec: both_m2m = old_field.many_to_many and new_field.many_to_many neither_m2m = not old_field.many_to_many and not new_field.many_to_many if both_m2m or neither_m2m: # Either both fields are m2m or neither is preserve_default = True if (old_field.null and not new_field.null and not new_field.has_default() and not new_field.many_to_many): field = new_field.clone() new_default = self.questioner.ask_not_null_alteration(field_name, model_name) if new_default is not models.NOT_PROVIDED: field.default = new_default preserve_default = False else: field = new_field self.add_operation( app_label, operations.AlterField( model_name=model_name, name=field_name, field=field, preserve_default=preserve_default, ) ) else: # We cannot alter between m2m and concrete fields self._generate_removed_field(app_label, model_name, field_name) self._generate_added_field(app_label, model_name, field_name)
def generate_altered_fields(self): """ Fields that have been altered. """ for app_label, model_name, field_name in sorted(self.old_field_keys.intersection(self.new_field_keys)): # Did the field change? old_model_name = self.renamed_models.get((app_label, model_name), model_name) old_field_name = self.renamed_fields.get((app_label, model_name, field_name), field_name) old_field = self.old_apps.get_model(app_label, old_model_name)._meta.get_field(old_field_name) new_field = self.new_apps.get_model(app_label, model_name)._meta.get_field(field_name) # Implement any model renames on relations; these are handled by RenameModel # so we need to exclude them from the comparison if hasattr(new_field, "rel") and getattr(new_field.rel, "to", None): rename_key = ( new_field.rel.to._meta.app_label, new_field.rel.to._meta.model_name, ) if rename_key in self.renamed_models: new_field.rel.to = old_field.rel.to old_field_dec = self.deep_deconstruct(old_field) new_field_dec = self.deep_deconstruct(new_field) if old_field_dec != new_field_dec: both_m2m = ( isinstance(old_field, models.ManyToManyField) and isinstance(new_field, models.ManyToManyField) ) neither_m2m = ( not isinstance(old_field, models.ManyToManyField) and not isinstance(new_field, models.ManyToManyField) ) if both_m2m or neither_m2m: # Either both fields are m2m or neither is preserve_default = True if (old_field.null and not new_field.null and not new_field.has_default() and not isinstance(new_field, models.ManyToManyField)): field = new_field.clone() new_default = self.questioner.ask_not_null_alteration(field_name, model_name) if new_default is not models.NOT_PROVIDED: field.default = new_default preserve_default = False else: field = new_field self.add_operation( app_label, operations.AlterField( model_name=model_name, name=field_name, field=field, preserve_default=preserve_default, ) ) else: # We cannot alter between m2m and concrete fields self._generate_removed_field(app_label, model_name, field_name) self._generate_added_field(app_label, model_name, field_name)
