Question

我正在为我的Django应用程序制作一个终端命令：

from django.core.management.base import BaseCommand, CommandError
from django.core.exceptions import FieldDoesNotExist
from django.apps import apps


class Command(BaseCommand):
    def add_arguments(self, parser):
        parser.add_argument(
            "--app",
            dest="app",
            required=True,
        )

        parser.add_argument(
            "--model",
            dest="model",
            required=True,
        )

        parser.add_argument(
            "--col",
            dest="col",
            required=True,
        )

    def handle(self, *args, **options):
        app_label = options.get('app')
        model_name = options.get('model')
        column_name = options.get('col')

        try:
            model = apps.get_model(app_label=app_label, model_name=model_name)
        except LookupError as e:
            msg = 'The model "%s" under the app "%s" does not exist!' \
                  % (model_name, app_label)
            raise CommandError(msg)
        try:
            column = model._meta.get_field(column_name)
        except FieldDoesNotExist as e:
            msg = 'The column "%s" does not match!' % column_name
            raise CommandError(msg)
        else:
            print(column, type(column))
            # Do stuff here with the column, model.

目前，column为<django.db.models.fields.IntegerField: column_name>。我希望model的此实例将column_name设置为100。如何以这种方式设置和保存此实例？

Answer 1

实际上，您需要首先根据过滤器或ID检索模型的实例，例如

model_instance = model.objects.get(pk=1)

您显然需要先确定要更新的实例。

然后您可以在实例

上执行以下操作

setattr(model_instance, 'column_name', 100)

这会将值100设置为属性名称＆＃39; column_name＆＃39;到模型实例。

然后您可以运行model_instance.save()，如果需要，可以将值保存到数据库中。

如果要创建新的模型实例，您可以执行以下任一操作：

model_instance = model(column_name=100)

或

model_instance = model()
setattr(model_instance, column_name, 100)

其次是

model_instance.save()

使用`get_field（）`后如何设置模型对象属性的值？

1 个答案: