python - 生成假数据以填充数据库

Question

我正在尝试使用 factory boy 和 faker 为我正在构建的网站生成一些虚假数据。这是我的 models.py:

# External Imports
from django.db import models
import uuid

# Internal Imports
from applications.models.application import Application
from users.models.user import User
from .session import Session

# Fake data
import factory
import factory.django
import factory.fuzzy
from datetime import datetime
from faker import Faker
from faker.providers import BaseProvider
import random


class ButtonClick(models.Model):
    """**Database model that tracks and saves button clicks for an application**
    """
    # identifier
    id = models.UUIDField(default=uuid.uuid4, primary_key=True, editable=False)

    # info
    button_name = models.CharField(max_length=128, null=True, blank=True)
    application = models.ForeignKey(
        Application, related_name='button_clicks', null=True, blank=True, on_delete=models.CASCADE)
    user = models.ForeignKey(
        User, related_name='button_clicks', null=True, blank=True,      on_delete=models.CASCADE)
    session = models.ForeignKey(
        Session, related_name='button_clicks', null=True, blank=True, on_delete=models.CASCADE)
        timestamp = models.DateTimeField(auto_now=True)

class Meta:
    db_table = 'button_clicks'
    ordering = ('-timestamp', )

def __str__(self):
    return f'{self.application} - {self.button_name}'

fake = Faker()
faker = Factory.create()


class ApplicationFactory(factory.DjangoModelFactory):
    class Meta:
        model = Application

    application = factory.LazyAttribute(lambda _: faker.word())


class FakeButtonClick(factory.django.DjangoModelFactory):
    class Meta:
        model = ButtonClick

    button_name = factory.Faker('first_name')
    application = factory.SubFactory(ApplicationFactory)
    user = factory.Faker('name')
    session = factory.Faker('random_int')
    timestamp = factory.Faker('date')

当我尝试在终端中运行以下代码时，出现错误:

>>> from analytics.models.button_click import FakeButtonClick
>>> for _ in range(200): FakeButtonClick.create()
... 

Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/Users/ryan/bloks/bloks-backend/venv/lib/python3.7/site-packages/factory/base.py", line 564, in create
    return cls._generate(enums.CREATE_STRATEGY, kwargs)
  File "/Users/ryan/bloks/bloks-backend/venv/lib/python3.7/site-packages/factory/django.py", line 141, in _generate
    return super(DjangoModelFactory, cls)._generate(strategy, params)
  File "/Users/ryan/bloks/bloks-backend/venv/lib/python3.7/site-packages/factory/base.py", line 501, in _generate
    return step.build()
  File "/Users/ryan/bloks/bloks-backend/venv/lib/python3.7/site-packages/factory/builder.py", line 279, in build
    kwargs=kwargs,
  File "/Users/ryan/bloks/bloks-backend/venv/lib/python3.7/site-packages/factory/base.py", line 315, in instantiate
    return self.factory._create(model, *args, **kwargs)
  File "/Users/ryan/bloks/bloks-backend/venv/lib/python3.7/site-packages/factory/django.py", line 185, in _create
    return manager.create(*args, **kwargs)
  File "/Users/ryan/bloks/bloks-backend/venv/lib/python3.7/site-packages/django/db/models/manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/Users/ryan/bloks/bloks-backend/venv/lib/python3.7/site-packages/django/db/models/query.py", line 431, in create
    obj = self.model(**kwargs)
  File "/Users/ryan/bloks/bloks-backend/venv/lib/python3.7/site-packages/django/db/models/base.py", line 482, in __init__
    _setattr(self, field.name, rel_obj)
  File "/Users/ryan/bloks/bloks-backend/venv/lib/python3.7/site-packages/django/db/models/fields/related_descriptors.py", line 219, in __set__
    self.field.remote_field.model._meta.object_name,
ValueError: Cannot assign "9714": "ButtonClick.application" must be a "Application" instance.

我过去使用 factory boy 和 faker 创建了一些非常简单的数据，但回溯似乎暗示我需要在我的 FakeButtonClick 类中创建一个应用程序实例？我检查了文档，应用程序似乎不是工厂男孩/伪造者的可用实例。我需要自己创建实例吗？也许是一个子工厂？

Answer 1

您的 ButtonClick 模型有 3 个字段定义为 ForeignKey:application、user 和 session 。

当您想要创建一个 ButtonClick 实例时，Django 要求您为定义为 ForeignKey 的每个字段提供一个有效值 — 在这里，这意味着提供模型实例或 None(因为那些 ForeignKey 可以为 null)。

对于 FactoryBoy，这意味着您必须:

1. 为每个模型定义一个 Factory 类。
2. 使用指向每个字段的工厂的 factory.SubFactory。

一个例子是:

class UserFactory(factory.django.DjangoModelFactory):
    class Meta:
        model = User
    username = factory.Faker('username')

class SessionFactory(factory.django.DjangoModelFactory):
    class Meta:
        model = Session
    uuid = factory.Faker('uuid4')
    user = factory.SubFactory(UserFactory)

class ApplicationFactory(factory.django.DjangoModelFactory):
    class Meta:
        model = Application
    name = factory.Faker('name')

class ButtonClickFactory(factory.django.DjangoModelFactory):
    class Meta:
        model = ButtonClick
    user = factory.SubFactory(UserFactory)
    # Ensure that click.user == click.session.user
    session = factory.SubFactory(SessionFactory, user=factory.SelfAttribute('..user'))
    application = factory.SubFactory(ApplicationFactory)

可以看看at the docs .

顺便说一下，FactoryBoy 的 faker integration ，不需要直接导入:factory.Faker('uuid4')等同于faker.Faker().uuid4()。