摇尾误差models.py中的new models.CharField

Question

我希望你们都好：）你能帮我一下吗。我是初学者。我正在用python发布一个新网站，我选择wagtail作为CMS。我想更改每个博客页面的模式，以便获得更多信息。但我遇到了一些问题：（

这段代码（blog/models.py）一切正常：

from django.db import models   
from django import forms

from modelcluster.fields import ParentalKey, ParentalManyToManyField
from wagtail.core.models import Page, Orderable
from wagtail.core.fields import RichTextField, StreamField
from wagtail.core import blocks
from wagtail.admin.edit_handlers import FieldPanel, InlinePanel, MultiFieldPanel, TabbedInterface, ObjectList, StreamFieldPanel
from wagtail.images.edit_handlers import ImageChooserPanel
from wagtail.images.blocks import ImageChooserBlock
from wagtail.search import index

from modelcluster.contrib.taggit import ClusterTaggableManager
from taggit.models import TaggedItemBase

from wagtail.snippets.models import register_snippet

class BlogIndexPage(Page):
    intro = RichTextField(blank=True)

    content_panels = Page.content_panels + [
        FieldPanel('intro', classname="full")
    ]


class BlogPageTag(TaggedItemBase):
    content_object = ParentalKey(
        'BlogPage',
        related_name='tagged_items',
        on_delete=models.CASCADE
    )



class BlogPage(Page):
    date = models.DateField("Post date")
    intro = models.CharField(max_length=250)
    body = RichTextField(blank=True)
    recette = RichTextField(blank=True)
    aliment = RichTextField(blank=True)
    forcealiment = RichTextField(blank=True)
    tags = ClusterTaggableManager(through=BlogPageTag, blank=True)
    categories = ParentalManyToManyField('blog.BlogCategory', blank=True)

    def main_image(self):
        gallery_item = self.gallery_images.first()
        if gallery_item:
            return gallery_item.image
        else:
            return None

    search_fields = Page.search_fields + [
        index.SearchField('intro'),
        index.SearchField('body'),
        index.SearchField('recette'),
        index.SearchField('aliment'),
        index.SearchField('forcealiment'),
    ]

    content_panels = Page.content_panels + [
        MultiFieldPanel([
            FieldPanel('date'),
            FieldPanel('tags'),
            FieldPanel('categories', widget=forms.CheckboxSelectMultiple),
        ], heading="Blog information"),
        FieldPanel('intro'),
        FieldPanel('body'),
        FieldPanel('recette'),
        FieldPanel('aliment'),
        FieldPanel('forcealiment'),
        InlinePanel('gallery_images', label="Gallery images"),
    ]


class BlogPageGalleryImage(Orderable):
    page = ParentalKey(BlogPage, on_delete=models.CASCADE, related_name='gallery_images')
    image = models.ForeignKey(
        'wagtailimages.Image', on_delete=models.CASCADE, related_name='+'
    )
    caption = models.CharField(blank=True, max_length=250)

    panels = [
        ImageChooserPanel('image'),
        FieldPanel('caption'),
    ]


class BlogTagIndexPage(Page):

    def get_context(self, request):

        # Filter by tag
        tag = request.GET.get('tag')
        blogpages = BlogPage.objects.filter(tags__name=tag)

        # Update template context
        context = super().get_context(request)
        context['blogpages'] = blogpages
        return context

@register_snippet
class BlogCategory(models.Model):
    name = models.CharField(max_length=255)
    icon = models.ForeignKey(
        'wagtailimages.Image', null=True, blank=True,
        on_delete=models.SET_NULL, related_name='+'
    )

    panels = [
        FieldPanel('name'),
        ImageChooserPanel('icon'),
    ]

    def __str__(self):
        return self.name

    class Meta:
        verbose_name_plural = 'blog categories'

但当我尝试添加一个新的领域“炊具”时，比如

cooker = models.CharField(max_length=250)

第一个stel可以：

(monProjetWagtail:3.7)[dulo0814@louisiane monProjetWagtail]$ python manage.py makemigrations
Migrations for 'blog':
  blog/migrations/0018_auto_20200522_1106.py
    - Remove field autobio from blogpage
    - Add field cooker to blogpage

第二步不行：（

(monProjetWagtail:3.7)[dulo0814@louisiane monProjetWagtail]$ python manage.py migrate
System check identified some issues:

WARNINGS:
?: (mysql.W002) MySQL Strict Mode is not set for database connection 'default'
        HINT: MySQL's Strict Mode fixes many data integrity problems in MySQL, such as data truncation upon insertion, by escalating warnings into errors. It is strongly recommended you activate it. See: https://docs.djangoproject.com/en/3.0/ref/databases/#mysql-sql-mode
Operations to perform:
  Apply all migrations: admin, auth, blog, contenttypes, home, sessions, taggit, wagtailadmin, wagtailcore, wagtaildocs, wagtailembeds, wagtailforms, wagtailimages, wagtailredirects, wagtailsearch, wagtailusers
Running migrations:
  Applying blog.0013_blogpage_autorpost...Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/home/dulo0814/virtualenv/monProjetWagtail/3.7/lib/python3.7/site-packages/django/core/management/__init__.py", line 401, in execute_from_command_line
    utility.execute()
  File "/home/dulo0814/virtualenv/monProjetWagtail/3.7/lib/python3.7/site-packages/django/core/management/__init__.py", line 395, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/dulo0814/virtualenv/monProjetWagtail/3.7/lib/python3.7/site-packages/django/core/management/base.py", line 328, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/home/dulo0814/virtualenv/monProjetWagtail/3.7/lib/python3.7/site-packages/django/core/management/base.py", line 369, in execute
    output = self.handle(*args, **options)
  File "/home/dulo0814/virtualenv/monProjetWagtail/3.7/lib/python3.7/site-packages/django/core/management/base.py", line 83, in wrapped
    res = handle_func(*args, **kwargs)
  File "/home/dulo0814/virtualenv/monProjetWagtail/3.7/lib/python3.7/site-packages/django/core/management/commands/migrate.py", line 233, in handle
    fake_initial=fake_initial,
  File "/home/dulo0814/virtualenv/monProjetWagtail/3.7/lib/python3.7/site-packages/django/db/migrations/executor.py", line 117, inmigrate
    state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
  File "/home/dulo0814/virtualenv/monProjetWagtail/3.7/lib/python3.7/site-packages/django/db/migrations/executor.py", line 147, in_migrate_all_forwards
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
  File "/home/dulo0814/virtualenv/monProjetWagtail/3.7/lib/python3.7/site-packages/django/db/migrations/executor.py", line 245, inapply_migration
    state = migration.apply(state, schema_editor)
  File "/home/dulo0814/virtualenv/monProjetWagtail/3.7/lib/python3.7/site-packages/django/db/migrations/migration.py", line 124, in apply
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
  File "/home/dulo0814/virtualenv/monProjetWagtail/3.7/lib/python3.7/site-packages/django/db/migrations/operations/fields.py", line 112, in database_forwards
    field,
  File "/home/dulo0814/virtualenv/monProjetWagtail/3.7/lib/python3.7/site-packages/django/db/backends/mysql/schema.py", line 80, in add_field
    super().add_field(model, field)
  File "/home/dulo0814/virtualenv/monProjetWagtail/3.7/lib/python3.7/site-packages/django/db/backends/base/schema.py", line 450, in add_field
    definition, params = self.column_sql(model, field, include_default=True)
  File "/home/dulo0814/virtualenv/monProjetWagtail/3.7/lib/python3.7/site-packages/django/db/backends/base/schema.py", line 223, in column_sql
    default_value = self.effective_default(field)
  File "/home/dulo0814/virtualenv/monProjetWagtail/3.7/lib/python3.7/site-packages/django/db/backends/base/schema.py", line 303, in effective_default
    return field.get_db_prep_save(self._effective_default(field), self.connection)
  File "/home/dulo0814/virtualenv/monProjetWagtail/3.7/lib/python3.7/site-packages/django/db/models/fields/__init__.py", line 821,in get_db_prep_save
    return self.get_db_prep_value(value, connection=connection, prepared=False)
  File "/home/dulo0814/virtualenv/monProjetWagtail/3.7/lib/python3.7/site-packages/django/db/models/fields/__init__.py", line 816,in get_db_prep_value
    value = self.get_prep_value(value)
  File "/home/dulo0814/virtualenv/monProjetWagtail/3.7/lib/python3.7/site-packages/wagtail/core/fields.py", line 111, in get_prep_value
    return json.dumps(self.stream_block.get_prep_value(value), cls=DjangoJSONEncoder)
  File "/home/dulo0814/virtualenv/monProjetWagtail/3.7/lib/python3.7/site-packages/wagtail/core/blocks/stream_block.py", line 260,in get_prep_value
    return value.get_prep_value()
AttributeError: 'datetime.datetime' object has no attribute 'get_prep_value'
(monProjetWagtail:3.7)[dulo0814@louisiane monProjetWagtail]$

有人能帮我吗

附言：我是法国人

Answer 1

错误消息显示错误发生在迁移0013_blogpage_autorpost上，而不是刚刚创建的0018_auto_20200522_1106迁移上。假设您没有在每个makemigrations步骤后运行./manage.py migrate（或者您可能在前面看到此错误）

错误引用的是StreamField-看起来您有一个datetime对象，其中应该有一个块。由于您的模型中现在没有任何StreamFields，我想这是您添加并随后删除的字段（但它仍然是迁移历史的一部分）。我的建议是删除编号为0013及以上的blog/migrations中的所有迁移文件，然后重新运行./manage.py makemigrations，这样您就有了一个新的迁移序列，而不会出现该错误。（通常情况下，删除迁移不是一个好主意，因为这意味着您的数据库可能最终处于与代码不匹配的状态-但在这种情况下，我认为这应该是安全的，因为从0013开始的迁移尚未运行。）