"django.core.exceptions.ValidationError" error

Question

I am writing a simple game in Django, all of things were right, but suddenly..., I was encountered by following error:

Django.v = 1.7
Python.v = 3.4

I don't know what is wrong with these codes:

    (test)alireza@alireza:~/test/test1$ python manage.py syncdb
    Operations to perform:
      Synchronize unmigrated apps: django_admin_bootstrapped, django_admin_bootstrapped_bootstrap3, crispy_forms
      Apply all migrations: contenttypes, admin, auth, arosis, sessions
    Synchronizing apps without migrations:
      Creating tables...
      Installing custom SQL...
      Installing indexes...
    Running migrations:
      Applying arosis.0008_auto_20150212_0826...Traceback (most recent call last):
      File "manage.py", line 10, in <module>
        execute_from_command_line(sys.argv)
      File "/home/alireza/test/lib/python3.4/site-packages/django/core/management/__init__.py", line 385, in execute_from_command_line
        utility.execute()
      File "/home/alireza/test/lib/python3.4/site-
...
...
...

        return self.to_python(value)
      File "/home/alireza/test/lib/python3.4/site-packages/django/db/models/fields/__init__.py", line 1252, in to_python
        params={'value': value},
    django.core.exceptions.ValidationError: ["'' value has an invalid format. It must be in YYYY-MM-DD HH:MM[:ss[.uuuuuu]][TZ] format."]

In my models.py:

class Move(models.Model):
    """docstring for Move"""
    x = models.IntegerField()
    y = models.IntegerField()
    comment = models.CharField(max_length=30)
    game = models.ForeignKey(Game)
    by_first_player = models.BooleanField(default=True)
    timestamp = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return "{}".format(self.comment)

    class Meta:
        get_latest_by = 'timestamp'

    def player(self):
        return self.game.first_player if self.by_first_player else self.game.second_player

I gave auto_now_add=True,

but at first, when I run :

python manage.py makemigrations

It asked me for entering a default value for DateTimeField()

What should I do?

0008_auto_20150212_0826.py

# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.db import models, migrations


class Migration(migrations.Migration):

    dependencies = [
        ('arosis', '0007_auto_20150211_1844'),
    ]

    operations = [
        migrations.AlterModelOptions(
            name='move',
            options={'get_latest_by': 'timestamp'},
        ),
        migrations.AddField(
            model_name='move',
            name='by_first_player',
            field=models.BooleanField(default=True),
            preserve_default=True,
        ),
        migrations.AddField(
            model_name='move',
            name='timestamp',
            field=models.DateTimeField(default='', auto_now_add=True),
            preserve_default=True,
        ),
    ]

Benjamin · Accepted Answer · 2015-07-12 05:49:08Z

17

I had a similar thing. Delete all migrations from your folder /migrations and then run python manage.py makemigrations and then python manage.py migrate. This worked for me.

answered Jul 12, 2015 at 5:49

Benjamin

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2 Comments

Clever Programmer Over a year ago

OMG I spent 4 hours bashing my head against the wall. THANK YOU!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Paweł Pedryc Over a year ago

that's cool in some cases, but what to do when you don't want to delete all data? how to fix just this one column with invalid data?

Alessandro Mariotti · Accepted Answer · 2015-02-12 10:58:05Z

1

As far as I understand, you already have a database which already has some "Move" entries in it.

If you add a column in a table which already has data in it, you'll need to provide a default value for that column, that the migration will set to all existing entries in the DB for the involved table (otherwise such entries will be invalid, unless null=True is specified as kwarg, if I remember correctly)

Furthermore, it is possible (happens to me ALL THE TIME), that you will need to set, in settings.py, the DATE_INPUT_FORMATS and the DATETIME_INPUT_FORMATS variables, accordingly to your locale and the way you're used to type dates. (See https://docs.djangoproject.com/en/1.7/ref/settings/#date-input-formats)

An example (In Italy, we have DD/MM/YYYY format):

DATE_INPUT_FORMATS = ( "%d/%m/%Y", )
DATETIME_INPUT_FORMATS = ( "%d/%m/%Y %H:%M", )

You django configuration is expecting the following format instead:

 YYYY-MM-DD HH:MM[:ss[.uuuuuu]][TZ]

(Stuff inside the square brackets is optional)

Edit: the auto_now_add kw arg tells that the field value should be set to "now" when adding (and not updating..) an entry

edited Feb 12, 2015 at 10:58

answered Feb 12, 2015 at 10:07

Alessandro Mariotti

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7 Comments

Alireza Ghaffari Over a year ago

Hi @Alessandro, I am doing anything with it and even I clear all of my models.py classes, but nothing :( I don't know what's wrong!

Alessandro Mariotti Over a year ago

Are you asked to input a default value when migrating? What do you type in when you're asked for a default value? You need to provide a valid date in the format django expects

Alessandro Mariotti Over a year ago

Can you post the 0008_auto_20150212_0826.py migration?

Alireza Ghaffari Over a year ago

Yes, I type ' ' (blank) when migrating asked me.

Alireza Ghaffari Over a year ago

I added 0008_auto ...py to the main question.

|

Burhan Khalid · Accepted Answer · 2015-02-12 11:05:14Z

0

It asked me for entering a default value for DateTimeField()

It is doing this because you have not specified a default, and the field is not optional. Since its a destructive change, you have to provide a default value.

You probably just hit enter and hence the exception, since a blank string is not a valid entry for DateTimeField.

The solution is to run migrate again, and this time provide a valid date and time string; which will be used for all existing rows in your database; example of a valid format is 2015-02-12 00:00

answered Feb 12, 2015 at 11:05

Burhan Khalid

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Comments

karuhanga · Accepted Answer · 2018-01-25 20:33:35Z

0

Also, if you're not afraid of getting your hands a little dirty, looking through the migrations files in that folder and finding the specific invalid field did it for me. Deleting all the migrations threw up a few errors for me.

answered Jan 25, 2018 at 20:33

karuhanga

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Comments

Paweł Pedryc · Accepted Answer · 2022-09-09 22:55:05Z

0

Solution (if you are using Visual Studio Code and you don't want to delete all files from the migrations folder):

Press ctr+shift+f

type the phrase that was seen as invalid.

For example:

django.core.exceptions.ValidationError: ['“09.09.2022” value has an invalid date format. It must be in YYYY-MM-DD format.']

so type 09.09.2022

Be sure that you are looking at all files!

Below the 'search' field, place in the 'replace' field a proper date: 2022.09.09

voila

answered Sep 9, 2022 at 22:55

Paweł Pedryc

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