What I need
I added an new app in my project and a separate database for it. I have created the Models for that app and now I need to migrate this models in this separate database
app name - authors_app
database name - authors
My code
python3 manage.py makemigrations authors_app
It creates the 0001_initial.py file which contains only models from my authors_app. So this step is OK
python3 manage.py migrate authors_app 0001_initial --database=authors
And this command runs not only my migrations from authors_app, but also migrations from my other app
Problem
I need to migrate only migrations from authors_app. But the migrate command runs the migrations from all apps. I have 58 migrations in my other app. And this command runs them all into the new database ...
Question
How can I run migrate for only authors_app
Update
Inside my authors_app Models I use one model from another app
from tibrains_app.models import Language
class AuthorLanguage(models.Model):
author = models.OneToOneField(Author, on_delete=models.CASCADE)
native_list = models.ManyToManyField(Language, related_name='author_native_languages')
all_list = models.ManyToManyField(Language, related_name='author_all_languages')
writing_list = models.ManyToManyField(Language, related_name='author_writing_languages')
And inside my 0001_initial file I have a dependencies
dependencies = [
('tibrains_app', '0058_book_history_period'),
]
Could this cause the problem?
Related
I am making changes to a model AppContactCnt to add new fields to handle deleting of records.
Here is that models.py
class AppContactCnt(models.Model):
id_cnt = models.AutoField(primary_key=True)
# idcst_cnt = models.IntegerField()
idcst_cnt = models.ForeignKey(AppCustomerCst, models.DO_NOTHING, db_column='idcst_cnt')
idctp_cnt = models.ForeignKey(AppContactTypeCtp, models.DO_NOTHING, db_column='idctp_cnt')
idtrp_cnt = models.IntegerField()
name_cnt = models.CharField(max_length=50)
phone_cnt = models.CharField(max_length=50, blank=True, null=True)
email_cnt = models.CharField(max_length=100, blank=True, null=True)
note_cnt = models.CharField(max_length=100, blank=True, null=True)
receives_emails_cnt = models.BooleanField(blank=True, null=True)
deleted_cnt = models.BooleanField(blank=True, null=True)
# date_deleted_cnt = models.DateTimeField(blank=True, null=True)
# deleted_by_cnt = models.CharField(max_length=100, blank=True, null=True)
class Meta:
db_table = 'app_contact_cnt'
app_label = 'easytrade20'
I tried to add in managed = True no change.
Also tried the following:
Delete all previous migration files and pycache files except init.
python manage.py migrate --fake-initial
python manage.py makemigrations
python manage.py migrate
I am still getting No changes detected
I am not sure how to proceed, any assistance is apprecaited.
You have set app_label = 'easytrade20' in the meta option, but Django is unable to detect an app named easytrade20 in your project. That's why there aren't any changes.
So, add easytrade20 to your INSTALLED_APPS or remove app_label = 'easytrade20' from the model's Meta, and try again to run your migrations.
try this:
python manage.py makemigrations [app_name]
python manage.py migrate
Problem
The app is likely not listed in INSTALLED_APPS located in settings.py, therefore Django has not registered your application and will not detect migrations that need to be run in that application.
Solution
Add easytrade20 to your INSTALLED_APPS and try again to run your migrations.
If the answers above didn't work for you I propose you to make a model and migrations based on an existing database. The steps to complete this task are outlined below.
Below I suggests that your app directory also called easytrade20.
I think that you already have a database that you are working with and all migrations have been applied to it. If not, and saving the
structure of migrations is not critical for you, then skip steps 2-3.
If any of your other apps have migrations that depend on easytrade20 migrations you need to repeat steps 2-5 for every of them (by renaming easytrade20 to your app name) before starting step 6 (and 6+ steps are required for that apps too).
0. Backup your files and database before changes
1. Update your Django version to the latest release
pip install django==3.0.* -U for 3.0.X (3.0.10 is latest release when I write these lines)
or
pip install django==3.1.* for latest one (3.1 have not so much differences from 3.0 and maybe it is right choice for you)
2. Check if all migrations are applied
Use showmigrations command to show applied migrations:
python manage.py showmigrations
You'll see structure with all apps and their migrations like this (app1 and app2 for example):
app1
[X] 0001_initial
app2
[X] 0001_initial
[X] 0002_some_other_migration
You'll see your apps and some django apps/third-party packages, like admin, auth, database, sessions etc.
If you'll see all [X] near every migration - all is fine, go on.
If you'll see some [ ] migration_name - try to apply these migrations first. Run python manage.py migrate app_name migration_name for every unapplied (unchecked) migration top down for every app (app_name for example).
3. Make new models based on your database structure
Use inspectdb to generate models:
python manage.py inspectdb > generated_models.py
File generated_models.py will be created. You need to copy from this file all models that you created for easytrade20 app. Replace your models.py with generated models and remove managed = False at least in the model AppContactCnt.
4. Remove information about easytrade20 migrations from database
python manage.py migrate --fake easytrade20 zero
And now if you'll run python manage.py showmigrations easytrade20 you'll see that all migrations unapplied.
5. Remove your migrations directory
That's it. Remove directory easytrade20/migrations completely.
Then if you'll run python manage.py showmigrations easytrade20 you'll see text (no migrations)
6. Generate new migrations
Run makemigrations command:
python manage.py makemigrations easytrade20
Folder easytrade20/migrations will be created. If not, then you'll need to check two things:
Your settings.py to ensure that easytrade20 included in your INSTALLED_APPS.
Your easytrade20 app settings. Ensure that your files have similar code:
# easytrade20/__init__.py
default_app_config = 'easytrade20.apps.EasyTradeConfig'
# easytrade20/apps.py
from django.apps import AppConfig
class EasyTradeConfig(AppConfig):
name = 'easytrade20'
7. Apply initial migration
If you have database with this table then fake migration:
python manage.py migrate easytrade20 --fake-initial
If not, then run without --fake-initial:
python manage.py migrate easytrade20
8. Make changes to your model, create and apply migrations
Change your models.py file.
Run python manage.py makemigrations easytrade20. New file in your easytrade20/migrations directory will be created.
Run python manage.py migrate easytrade20 to apply new migration.
Make sure your app is registered inside the settings.py, and the INSTALLED_APP section.
Django doesn't respond to making the migrations to the model in the new app.
I deleted the app then made a new one, but still doesn't respond. I deleted the old migration and makemigrations, Django only respond to the first model which I have done before this problem
(venv) F:\My site>python manage.py makemigrations
No changes detected
(venv) F:\My site>python manage.py makemigrations blog
No installed app with label 'blog'.
What you have to do is set your new app in the INSTALLED_APPS of Django settings.py.
INSTALLED_APPS = [
...,
'blog'
]
I have MySQL database in backed but when i change any model i does not reflect in backend
python manage.py makemigration app_name
python manage.py migrate
but it show no migrations applied
does mysql does nor support migrations
my model
class blog(models.Model):
name = models.CharField(max_length=10)
try fake migration
python manage.py -fake app_name
Be sure that you already added app_name to INSTALLED_APPS list
I tried Googling this problem, but I mostly saw answers that were from versions of Django where South was needed for migration and/or syncdb was still a thing. The ones that were relevant matched the symptom, but not the cause.
I started with the default project/app that Django creates when you do django-admin startproject project-name and django-admin startapp products.
models.py
from django.db import models
from django.contrib.auth.models import User
from django.core.exceptions import ObjectDoesNotExist
# Create your models here.
class Artist(models.Model):
user = models.OneToOneField(User, null=True, blank=True)
name = models.CharField(max_length=50)
def __str__(self): return "<Artist: %s>"%self.name
class Category(models.Model):
artists = models.ManyToManyField(Artist)
name = models.CharField(max_length=50)
desc = models.CharField(max_length=200)
My process:
python manage.py flush to clear the database
rm -rf products\migrations to delete prior migrations
python manage.py migrate
Output:
Operations to perform:
Apply all migrations: sessions, contenttypes, auth, admin
Running migrations:
No migrations to apply.
python manage.py makemigrations products
Output:
Migrations for 'products':
0001_initial.py:
- Create model Artist
- Create model Category
python manage.py migrate
Output:
Operations to perform:
Apply all migrations: contenttypes, admin, sessions, products, auth
Running migrations:
No migrations to apply.
At this point, I'm confused. Aren't there migrations to be applied, and yet there aren't any? I press on nonetheless.
python manage.py shell
In this shell, I enter these commands:
>>> from products.models import *
>>> artist = Artist(name="foo")
>>> artist.save()
>>> categ = Category(name="bar", desc="baz")
>>> categ.save()
>>> categ.artists.add(artist)
At this point, I get a huge error traceback. The problem seems to be this:
django.db.utils.OperationalError: no such table: products_category_artists
I see the same error if I try to use the built-in admin site.
My guess is that the problem is that migrations aren't actually being applied or that a particular table isn't being created, but I don't know how to fix either of these problems.
There is a table generated by django called django_migrations which keeps track of what migrations have been applied. If you delete your migrations, re-generate them and try to migrate without deleting the records from the table than django will think it already applied them. You should never delete your migrations, it will cause django to get confused.
If you are actively developing and want to skip the entire migrations system you can, but once you start using migrations, never delete them. Here is what I use while developing a new project:
dropdb mydb && createdb mydb && python manage.py migrate --run-syncdb && python manage.py loaddata initial
First, it drops the database and all data. Then it creates an empty one. The --run-syncdb generates the schema and the loaddata loads data from a fixtures file.
So, if you are still developing and can delete all your data and move what you care about to a fixtures file than you can delete all your migration folders and run the command above each time you change your model.
I have been trying to synchronize changes to a model in a Django app using migrations in 1.7 (postgres 9.1 - let me know if you need more details of my environment), but manage.py migrate doesn't seem to do anything, and sqlmigrate doesn't emit any SQL.
I thought Django 1.7 - "No migrations to apply" when run migrate after makemigrations might be applicable to my situation, and I did find some history in the django_migrations table in my database. I deleted the records for the app I am trying to migrate.
Recently I gave up on getting the alter table statements to generate/run and dropped the original version of the table. And while manage.py migrate states it is applying the migration, nothing happens to the database.
Here are the steps I've been trying:
Delete the history.
rm -r myapp/migrations
../manage.py dbshell
myapp_db=> delete from django_migrations where app='myapp'
Create an initial migration.
cp myapp/models.py.orig myapp/models.py
../manage.py makemigrations myapp
../manage.py migrate
manage.py migrate returns the following:
....
Running migrations:
Applying myapp.0001_initial... FAKED
Then I swap in the new models and generate a new migration.
cp myapp/models.py.new myapp/models.py
../manage.py makemigrations myapp
The result of makemigrations is in myapp/migrations/0002_notificationlog.py:
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import models, migrations
class Migration(migrations.Migration):
dependencies = [
('myapp', '0001_initial'),
]
operations = [
migrations.CreateModel(
name='NotificationLog',
fields=[
('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
('tstamp', models.DateTimeField(help_text=b'Log time', auto_now_add=True)),
('recipient', models.CharField(max_length=100)),
('subject', models.TextField()),
],
options={
},
bases=(models.Model,),
),
]
Run this migration:
../manage.py migrate
manage.py migrate acts like everything is OK:
....
Running migrations:
Applying myapp.0002_notificationlog... OK
I can see the log entries appear in django_migrations, but the table is not created.
I'm lost. Any idea what to try next?
Update
When running migrate -v 3 as requested, I see
Running pre-migrate handlers for application auth
followed by a similar line for each installed app.
Then
Loading 'initial_data' fixtures...
Checking '/var/www/environment/default/myproj/myproj' for fixtures...
No fixture 'initial_data' in '/var/www/environment/default/myproj/myproj'.
repeated a total of 13 times, the number of unmanaged apps.
Then
Running migrations:
Applying myapp.0001_initial... FAKED
followed by
Running post-migrate handlers for application auth
with a similar line for each installed app.
For migration 0002, the output is the same, except for
Running migrations:
Applying myapp.0002_notificationlog... OK
Note also that sqlmigrate doesn't output anything either:
../manage.py sqlmigrate myapp 0002 -v 3
Produces nothing at all.
Update 2
I copied myapp into a new project and was able to run migrations on it, but migrations stopped working when I imported my main project settings. Are there settings I should be aware of that could affect migration execution, particularly if I've been using South with previous versions of Django?
The problem disappeared with generic project settings and reappeared with my old, complex project settings. I tracked the problem down to a database Router class that was missing an allow_migrate method.
DATABASE_ROUTERS = [ 'myproj.routers.DatabaseAppsRouter', ]
I use this router to handle queries for a separate app in the project (readonly/MySQL).
Sadly I can't blame anyone but myself, since the Django documentation states clearly:
Note that migrations will just silently not perform any operations on a model for which [allow_migrate] returns False. (link)
I had created this router some time ago and didn't add the allow_migrate method to my router class when I upgraded to Django 1.7. When I added the method and made sure it returned True when needed, migrations run and the problem is solved.