tib*_*key 3 python authentication django django-models
我是 django 的新手，我想修改我的模型（它已经在我的 sqlite3 数据库中）而不妨碍我的整个项目。上次我修改模型时花了几个小时才修复它，因为我对整个项目进行了窃听。所以我不想犯同样的错误，你们能帮我处理命令吗？感谢您的帮助
models.py（目前）
from django.db import models
THE_GENDER = [
("Monsieur", "Monsieur"),
("Madame", "Madame")
]
class Post(models.Model):
name = models.CharField(max_length=100)
email = models.CharField(max_length=100)
gender = models.CharField(max_length=8, choices=THE_GENDER)
number = models.CharField(max_length=100)
def __str__(self):
return self.name
我想要对模型进行的编辑（我想将作者用户添加到模型中。所以我知道谁在制作表单。）
from django.db import models
from django.contrib.auth.models import User
THE_GENDER = [
("Monsieur", "Monsieur"),
("Madame", "Madame")
]
class Post(models.Model):
name = models.CharField(max_length=100)
email = models.CharField(max_length=100)
gender = models.CharField(max_length=8, choices=THE_GENDER)
number = models.CharField(max_length=100)
author = models.ForeignKey(User, on_delete=models.CASCADE)
def __str__(self):
return self.name
我的 admin.py 文件（不确定是否需要保持不变或修改它）
from django.contrib import admin
from .models import Post
admin.site.register(Post)
我的 forms.py 文件
from django import forms
from .models import Post
from crispy_forms.helper import FormHelper
class post_form(forms.ModelForm):
def __init__(self, *args, **kwargs):
super(post_form, self).__init__(*args, **kwargs)
self.helper = FormHelper(self)
class Meta:
model = Post
fields = ["name", "email", "gender", "number"]
视图.py
from django.shortcuts import render
from django.http import HttpResponse
from .forms import post_form
# Create your views here.
def home(request):
form = post_form(request.POST or None)
if form.is_valid():
form.save()
context = {
"form": form
}
return render(request, "sms/home.html", context)
详细说明我上面的评论......
\n\n在 Django 中添加新的不可为 null 的foreignkey通常是一个三步过程。
\n\nnull=True，然后运行makemigrations。这将创建一个将添加该字段的迁移，没有什么特别的。执行此迁移将添加一列，其中所有行都具有NULL该值。makemigrations --empty)，然后编辑该迁移以包含数据迁移步骤。您需要根据您的业务逻辑，为新外键选择一些值。null=False并创建第三个迁移makemigrations。Django 会问你是否以某种方式处理过nulls \xe2\x80\x93 你需要说“是的，我发誓我已经”（因为你已经这样做了，在上面的步骤 2 中）。在实践中，对于OP问题的简化版本，我们需要添加一个用户外键：
\n\nclass Post(models.Model):\n name = models.CharField(max_length=100)\nclass Post(models.Model):\n name = models.CharField(max_length=100)\n author = models.ForeignKey(User, null=True, on_delete=models.CASCADE))\n$ python manage.py makemigrations\nMigrations for \'something\':\n something/migrations/0002_post_author.py\n - Add field author to post\n$ python manage.py makemigrations something --empty -n assign_author\nMigrations for \'something\':\n something/migrations/0003_assign_author.py\n与往常一样，可以在手册中找到有关数据迁移的更多信息。
\n\nclass Post(models.Model):\n name = models.CharField(max_length=100)\nclass Post(models.Model):\n name = models.CharField(max_length=100)\n author = models.ForeignKey(User, null=True, on_delete=models.CASCADE))\n如实回答问题 \xe2\x80\x93 您刚刚添加了 RunPython 操作。
\n\n$ python manage.py makemigrations something -n post_author_non_null\nYou are trying to change the nullable field \'author\' on something. to non-nullable without a default; we can\'t do that (the database needs something to populate existing rows).\nPlease select a fix:\n 1) Provide a one-off default now (will be set on all existing rows with a null value for this column)\n 2) Ignore for now, and let me handle existing rows with NULL myself (e.g. because you added a RunPython or RunSQL operation to handle NULL values in a previous data migration)\n 3) Quit, and let me add a default in models.py\nSelect an option: 2\nMigrations for \'something\':\n something/migrations/0004_post_author_non_null.py\n - Alter field author on post\n运行migrate现在将运行这三个迁移，并且您的模型将不会author丢失数据。