问题
I have some models like this:
class Category(models.Model):
class Meta:
ordering = ['name']
name = models.CharField(max_length=100)
text = models.TextField(blank=True)
def __str__(self):
return self.name
class Tag(models.Model):
name = models.CharField(max_length=100)
def __str__(self):
return self.name
class Tool(models.Model):
name = models.CharField(max_length=30, null=True, default='')
url = models.URLField(max_length=250, null=True, default='')
image_url = models.URLField(max_length=250, null=True, default='', blank=True)
about = models.TextField(default='', null=True, blank=True)
tags = models.ManyToManyField( Tag, related_name="tools" , blank=True)
category = models.ForeignKey(Category, on_delete=models.CASCADE, blank=True,null=True, related_name="category1")
altcategory = models.ForeignKey(Category, on_delete=models.CASCADE, blank=True,null=True, related_name="category2")
And everything seem ok, except when I go to add a tag to a Tool in the Admin screens. I can create a Tool and Tag but when I select a tag in the taglist in the Admin screens and Save I get:
The above exception (syntax error at or near "ON" LINE 1: ...ls_tool_tags" ("tool_id", "tag_id") VALUES (1, 2) ON CONFLIC... ^ ) was the direct cause of the following exception:
with the sql:
('INSERT INTO "tools_tool_tags" ("tool_id", "tag_id") VALUES (%s, %s) ON '
'CONFLICT DO NOTHING')
The DEBUG screen is saying the error is at "tag_id", is strange...
I hope it's not a version thing, since I'm using Heroku and have been really impressed with how everything "just works". My Django version is '3.0.4' and Postgres 12.2.
回答1:
I don't think ManyToMany works out of the box. So I had to create a "through" model... and change the admin form to this...
models.py
from django.db import models
from django.contrib.contenttypes.fields import GenericForeignKey, GenericRelation
from django.contrib.auth.models import User
from django.utils.html import format_html
from django.contrib.contenttypes.models import ContentType
class Category(models.Model):
class Meta:
ordering = ['name']
name = models.CharField(max_length=100)
text = models.TextField(blank=True)
def __str__(self):
return self.name
class Tag(models.Model):
name = models.CharField(max_length=100)
def __str__(self):
return self.name
class Tool(models.Model):
name = models.CharField(max_length=30, null=True, default='')
url = models.URLField(max_length=250, null=True, default='')
image_url = models.URLField(max_length=250, null=True, default='', blank=True)
about = models.TextField(default='', null=True, blank=True)
tags = models.ManyToManyField(
Tag,
through="PageTags",
through_fields=('tool', 'tag'))
category = models.ForeignKey(Category, on_delete=models.CASCADE, blank=True,null=True, related_name="category1")
altcategory = models.ForeignKey(Category, on_delete=models.CASCADE, blank=True,null=True, related_name="category2")
def _get_thumbnail(self):
return format_html(u'<img src="{}" width="150"/>', self.image_url)
_get_thumbnail.allow_tags = True
def _get_link(self):
return format_html(u'<a href="{}" target="_blank"/>{}</a>', self.url, self.url)
_get_link.allow_tags = True
def __str__(self):
return self.name + ": " + self.url
class PageTags(models.Model):
tag = models.ForeignKey(Tag , on_delete=models.CASCADE, )
tool= models.ForeignKey(Tool , on_delete=models.CASCADE, )
amount = models.IntegerField(default=0)
... and admin.py to this...
from django.contrib import admin
from django.contrib.admin import TabularInline
#from django.contrib.contenttypes.admin import GenericTabularInline
from django.utils.html import format_html_join
from django.utils.safestring import mark_safe
from .models import Tool, Category, Tag, PageTags
class PageTagsInline(admin.TabularInline):
model = PageTags
extra = 1
class ToolAdmin(admin.ModelAdmin):
#fields = ('name', )
list_display = ('name','_get_link','category','altcategory', "_get_thumbnail", )
list_filter = ('category',)
search_fields = ['name', "about"]
filter_horizontal = ('tags',)
inlines = [PageTagsInline,]
admin.site.register(Tag)
admin.site.register(Category)
admin.site.register(Tool, ToolAdmin)
And the interface is different, not like the permissions widgets, but OK... at least not bombing the admin.
来源:https://stackoverflow.com/questions/60625639/manytomanyfield-breaking-in-admin-screens-and-shouldnt-be