[Django]-How to store a dictionary in a Django database model's field

6๐Ÿ‘

โœ…

Probably the cleanest thing to do would be to create another โ€œProductsโ€ table and have a many-to-many relationship. (See here: https://docs.djangoproject.com/en/dev/topics/db/models/#many-to-many-relationships . In the docs they use the example of a pizza having many toppings.)

The other option would be to serialize your bill_products. In that case, youโ€™d do something like:

bill_products = json.dumps([rand_products])

This would be outside of the for loop (although, in your example above, rand_products is only a single value, so youโ€™ll need to fix that).

๐Ÿ‘คgdw2

21๐Ÿ‘

I just discovered the django-jsonfield package, which

is a reusable Django field that allows you to store validated JSON in your model.

Looks like a viable option to achieve what you want.

๐Ÿ‘คramiro

10๐Ÿ‘

One convenient way to store a JSON representation in a model is to use a custom field type:

class JSONField(models.TextField):
    """
    JSONField is a generic textfield that neatly serializes/unserializes
    JSON objects seamlessly.
    Django snippet #1478

    example:
        class Page(models.Model):
            data = JSONField(blank=True, null=True)


        page = Page.objects.get(pk=5)
        page.data = {'title': 'test', 'type': 3}
        page.save()
    """

    __metaclass__ = models.SubfieldBase

    def to_python(self, value):
        if value == "":
            return None

        try:
            if isinstance(value, basestring):
                return json.loads(value)
        except ValueError:
            pass
        return value

    def get_db_prep_save(self, value, *args, **kwargs):
        if value == "":
            return None
        if isinstance(value, dict):
            value = json.dumps(value, cls=DjangoJSONEncoder)
        return super(JSONField, self).get_db_prep_save(value, *args, **kwargs)

I saved this utils/fields.py and in my model from utils.fields import JSONField. There are many more goodies in the django-annoying app, which is where this snippet came from.

10๐Ÿ‘

Using a custom field type is my preferred solution โ€“ Iโ€™d rather have a few lines of custom code than support an entire 3rd party library for a single field type. Tony Abou-Assaleh has a great solution, but wonโ€™t work for newer versions of Django.

This is verified to work with Django 1.10.4

import json

from django.db import models
from django.core.serializers.json import DjangoJSONEncoder


class JSONField(models.TextField):
    """
    JSONField is a generic textfield that neatly serializes/unserializes
    JSON objects seamlessly.
    Django snippet #1478

    example:
        class Page(models.Model):
            data = JSONField(blank=True, null=True)


        page = Page.objects.get(pk=5)
        page.data = {'title': 'test', 'type': 3}
        page.save()
    """

    def to_python(self, value):
        if value == "":
            return None

        try:
            if isinstance(value, str):
                return json.loads(value)
        except ValueError:
            pass
        return value

    def from_db_value(self, value, *args):
        return self.to_python(value)

    def get_db_prep_save(self, value, *args, **kwargs):
        if value == "":
            return None
        if isinstance(value, dict):
            value = json.dumps(value, cls=DjangoJSONEncoder)
        return value
๐Ÿ‘คRico

4๐Ÿ‘

If postgres is your backend, consider the hstore field which has native support from django

๐Ÿ‘คwjin

3๐Ÿ‘

I think that I would create the field as models.CharField() and then encode the dictionary as a JSON string and save that string into the database. Then you can decode the JSON string back into a dictionary when you read it out.

๐Ÿ‘คbrian buck

3๐Ÿ‘

You can use serialization/deserialization from pickle module:

http://docs.python.org/library/pickle.html

1๐Ÿ‘

If using PostGres you can store it in natively supported JSON field:
https://docs.djangoproject.com/en/dev/ref/contrib/postgres/fields/#jsonfield

Otherwise Iโ€™d recommend @ramiro answer with 3rd party lib https://stackoverflow.com/a/16437627/803174

๐Ÿ‘คKangur

1๐Ÿ‘

according to Django doc you can use :

from django.contrib.postgres.fields import JSONField
from django.db import models

class Dog(models.Model):
    name = models.CharField(max_length=200)
    data = JSONField()

    def __str__(self):
        return self.name

and create with this :

Dog.objects.create(name='Rufus', data={
     'breed': 'labrador',
     'owner': {
         'name': 'Bob',
         'other_pets': [{
             'name': 'Fishy',
         }],
     },
})

I hope this can assist you.

๐Ÿ‘คhassanzadeh.sd

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