how to define a json type to a model field from django models

Question

Can anyone tell me how to define a json data type to a particular field in models.

I have tried this

from django.db import models
import jsonfield

class Test(models.Model):
    data = jsonfield.JSONField()

but when I say python manage.py sqlall xyz its taking the data field as text

BEGIN;
CREATE TABLE "xyz_test" (
   "data" text NOT NULL
)
;

I still tried to insert json data into that field but its giving error as :

ERROR:  value too long for type character varying(15)

someone please help. Thanks in Advance.

Well, in the background [JSONField actually *is* a TextField](https://github.com/bradjasper/django-jsonfield/blob/master/jsonfield/fields.py#L142), so that's not a problem, that's the expected behavior. However, the 15-chars limit is a tad weird - can you share the value you were trying to save? — yuvi, Sep 17 '14 at 07:22
@yuvi this is the value - {'name':'xyz', 'email':'xyz@gmail.com', 'phone':'0123456789'} — G-Coder, Sep 17 '14 at 07:29
I just recreated your model and was able to save that exact value to a jsonfield. Are you sure it's the jsonfield causing that error and not some different field that has a 15 chars limit? — yuvi, Sep 17 '14 at 07:39
ya its for that text field, anyways can you please post the procedure that you followed or syntax. — G-Coder, Sep 17 '14 at 07:52
I copied your exact code, and it worked (both when I passed the json as a python dictionary and as a JSON string). Please post your code that produces the error below — yuvi, Sep 17 '14 at 08:04

score 7 · Accepted Answer · edited Apr 11 '18 at 08:21

7

In the background JSONField actually is a TextField, so that output from sqlall is not a problem, that's the expected behavior.

Further, I recreated your model and it worked just fine, both when entering the value as a string and as a python dictionary, no character limitation whatsoever. So my best guess it that the issue is a completely unrelated field that does have a 15 chars limit.

edited Apr 11 '18 at 08:21

Bharathi

121
1
8

answered Sep 17 '14 at 08:19

yuvi

18,155
8
56
93

score 3 · Answer 2 · answered May 22 '17 at 15:57

3

A JSONField data type has been added to Django for certain databases to improve handling of JSON. More info is available in this post: Django 1.9 - JSONField in Models

answered May 22 '17 at 15:57

Ben

4,798
3
21
35

score 3 · Answer 3 · edited Dec 02 '20 at 08:41

3

You can try this:

from django.contrib.postgres.fields import JSONField

class Test(models.Model):
    data = models.JSONField()

edited Dec 02 '20 at 08:41

funie200

3,688
5
21
34

answered Dec 02 '20 at 07:22

poonam shinde

31
2

why are we importing `from django.contrib.postgres.fields import JSONField` if at the end we have to use `models.JSONField()`? – Hammad Mar 30 '22 at 08:47
1

"django.contrib.postgres.fields.JSONField is removed except for " "support in historical migrations." Use django.db.models.JSONField instead. – Elcast May 17 '22 at 19:16

Benyamin Jafari · Answer 4 · 2022-01-20T15:59:09.813

0

First install django-jsonfield pypi package:

pip install django-jsonfield

Then simply use it:

from jsonfield import JSONField

class MyModel(models.Model):
    custom_field = JSONField(
        default=dict
    )

edited Jan 20 '22 at 15:59

answered Jan 15 '22 at 12:22

Benyamin Jafari

27,880
26
135
150

how to define a json type to a model field from django models

4 Answers4