英文:
Django ModelMultipleChoiceField problem to save data in DB
问题
You should use a models.ManyToManyField field in models.py to make it work again. Here's the updated code:
models.py
from django.db import models
class Record(models.Model):
testrever = models.ManyToManyField('YourModelNameHere')
Replace 'YourModelNameHere' with the actual name of the model you want to use for the testrever field. This will allow you to establish a many-to-many relationship with another model, which should work for your scenario.
英文:
I used to have a Multi select box in my form filled with a JSON list
forms.py
FRUIT_CHOICES= [
('Oranges', 'Oranges'),
('Cantaloupes', 'Cantaloupes'),
('Mangoes', 'Mangoes'),
('Honeydews', 'Honeydews')
]
class AddRecordForm(forms.ModelForm):
testrever = forms.MultipleChoiceField(choices=FRUIT_CHOICES)
And so I used a JSON field in my models.py like this
models.py
class Record(models.Model):
testrever = models.JSONField(max_length=500)
It worked like a charm and I was able to save the selection and load it back when the form was recalled.
But now in forms.py I need to modify the forms.MultipleChoiceField to forms.ModelMultipleChoiceField which is populated by a queryset like this
class AddRecordForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
self.storage_pk = kwargs.pop('pk')
super(AddRecordForm, self).__init__(*args, **kwargs)
self.fields['testrever'].queryset = BDC.objects.filter(ref=self.storage_pk).values_list('model', flat=True)
testrever = forms.ModelMultipleChoiceField(widget=forms.widgets.SelectMultiple, queryset=None)
class Meta:
model = Record
exclude = ("user",)
fields = ['id','first_name','last_name','email', 'phone' ,'address', 'city' ,'state' ,'zipcode' ,'regarde' ,'testrever']
So now my models.JSONField in models.py is no longer working since I'm not rendering a JSON list format anymore.
What kind of field should I use in models.py to make it work again?
答案1
得分: 1
如果您选择另一个模型的零个、一个或多个项目，则使用ManyToManyField <sup>[Django-doc]</sup>：
<pre><code>class Fruit(models.Model):
name = models.CharField(max_length=128, unique=True)
def __str__(self):
return name
class Record(models.Model):
testrever = models.<b>ManyToManyField(</b>Fruit, blank=True<b>)</b></code></pre>
这也使用ModelMultipleChoice字段作为默认表单字段。因此，您只需插入不同的小部件：
<pre><code>class RecordForm(forms.ModelForm):
class Meta:
model = Record
fields = 'all'
widgets = {'testrever': <b>forms.SelectMultiple</b>}</code></pre>
虽然大多数数据库现在提供JSON字段，这对于非结构化数据很有用，但对于结构化数据来说，使用JSONField不是一个好主意，因为它违反了第一范式 <sup>[维基]</sup>。
英文:
If you pick zero, one or multiple items of another model, you use a ManyToManyField <sup>[Djangp-doc]</sup>:
<pre><code>class Fruit(models.Model):
name = models.CharField(max_length=128, unique=True)
def __str__(self):
return name
class Record(models.Model):
testrever = models.<b>ManyToManyField(</b>Fruit, blank=True<b>)</b></code></pre>
This also uses a ModelMultipleChoice field as default form field. So you only have to plug in a different widget:
<pre><code>class RecordForm(forms.ModelForm):
class Meta:
model = Record
fields = 'all'
widgets = {'testrever': <b>forms.SelectMultiple</b>}</code></pre>
while most databases offer a JSON field nowadays, which is useful for unstructered data, for structured data, using a JSONField is not a good idea as it violates first normal form <sup>[wiki]</sup>.
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