Reinstalling Django App - Data tables not re-created - python

I am trying to reinstall one of my apps on my project site. These are the steps that I have followed to do so:
Removing the name of the installed app from settings.py
Manually deleting the app folder from the project folder
Manually removing the data tables from PostgreSQL
Copying the app folder back into the project folder; making sure that all files, except __init__.py is removed.
Run python manage.py sqlmigrate app_name 0001
Run python manage.py makemigrations app_name
Run python manage.py migrate app_name
Run python manage.py makemigrations
Run python manage.py migrate
However, after all these steps the message I am getting is that there are "no changes detected" and the data tables have not been recreated in the database, PostgreSQL.
Am I missing some additional steps?

I think I might have managed to solve the problem. The command, python manage.py sqlmigrate app_name 0001, produces the SQL statements required for the table creation. Thus, I copied and paste the output into the PostgreSQL console and got the tables created. It seems to work for now, but I am not sure if there will be repercussions later.

Related

Relation does not exist error in Django

I know there are many questions about this problem, I looked through the solutions and unfortunately none of them worked for me.
I created a new app called "usermanagement", and added a model to the app. After adding the model I added usermanagement to INSTALLED_APPS in settings. Then I ran python manage.py makemigrations, and python manage.py migrate. This all worked fine! I also did try running the migrations with the app-name.
The problems start when I try to add a new instance of the model to the database in the Python-Django shell, by using:
>>>a = ClubOfficial(name="randomName", email="randomemail#random.com")
>>>a.save()
I get the following error:
django.db.utils.ProgrammingError: relation
"usermanagement_clubofficial" does not exist
LINE 1: INSERT INTO "usermanagement_clubofficial" ("name", "email") ...
Below is the model code:
class ClubOfficial(models.Model):
name = models.CharField(max_length=254)
email = models.EmailField(max_length=254)
If it helps, I use postgresql, and have tried restarting the server. The other apps in the program also work perfectly fine, it is just usermanagemenet that has this problem.
Does anyone know what could be going wrong?
Thank you for your time!
Note: I created a new app now with a different name, copy-pasted things from usermanagement and everything worked fine. I think the problem might be that before there was an app named usermanagement which was deleted, before I created it again. Maybe that messed up the database somehow.
TL;DR: Make sure your app's migrations folder has an __init__.py file. If it isn't there, create it again as an empty file.
I ran into this. In my case I had a previously working django app, not yet moved to production, so I deleted everything in my app's migrations folder, then using django extensions I wiped the postgresql database and cached files with:
./manage.py clear_cache
./manage.py clean_pyc
./manage.py reset_schema
./manage.py reset_db
# then deleted all files (including __init__.py) from my app's migrations folder.
I verified that my postgresql database had no tables. I then ran:
./manage.py makemigrations
./manage.py migrate
Which gave the output:
No changes detected
./manage.py migrate
Operations to perform:
Apply all migrations: admin, auth, contenttypes, sessions
Running migrations:
Applying contenttypes.0001_initial... OK
(about 11 more lines of output here which are similar)
It is notable that my model's names where nowhere in the migration. I printed the tables in my postgresql database and the Widget and Section tables were both missing. Running the app gave me this error (I substituted 'app' and 'model' for their real names):
ProgrammingError at /my_path
relation "app_model" does not exist
LINE 1: ..."."my_field", "app_model"."my_field" FROM "appname...
So the tables for the models were not being created in the database. My app's migrations folder was also completely empty. The solution was to just add an empty __init__.py to my app's migrations folder, and after that running makemigrations was able to create and save the migration file in the folder. This could then be executed with migrate. You can test this for yourself by running makemigrations with and without the __init__.py in the migrations/ folder.
This solution was not mine but one given by user Ljubitel on another post but it was not the accepted answer there, but the accepted answer didn't work for me so I wrote this solution here to hopefully help others.
I had this same problem, but all I had to do was run
$ python manage.py makemigrations
and
$ python manage.py migrate
In case you have deleted your migration folder.
Create a folder called migration in whatever app name you have created and then create a file in the migration folder called __init__.py
In my case I was pointing to a different databases between my local server and the production server. The database that the production server was pointing to was a few versions behind, so the server could not locate the relation. If your issue were localized to one environment, check the configs first.
Another method to fix relation does not exist error
Create same table in db(postgre, mysql) using sql query tool
now comment your model in models.py and admin.py
run migration using :
python manage.py makemigrations app_name
python manage.py migrate
now uncomment and run migrations command again
I encountered same issue and fixed using following method, I am using postgres(pgadmin 4).

Django Makemigrations not working in version 1.10 after adding new table

I added some table models in models.py for the first time running the app and then ran python manage.py makemigrations followed by python manage.py migrate. This works well but after adding two more tables it doesn't work again.
It created migrations for the changes made but when I run python manage.py migrate nothing happens. My new tables are not added to the database.
Things I have done:
Deleted all files in migrations folder and then run python manage.py makemigrationsfollowed by python manage.py migrate but the new tables are not still not getting added to the database even though the new table models show in the migration that was created i.e 0001_initial.py.
Deleted the database followed by the steps in 1 above but it still didn't solve my problem. Only the first set of tables get created.
Tried python manage.py makemigrations app_name but it still didn't help.
I have run into this problem before and found that running manage.py for specific tables in this fashion worked:
python manage.py schemamigration mytablename --auto
python manage.py migrate
Also make sure that your new table is listed under INSTALLED_APPS in your settings.py.
Can you post your models?
Have you edited manage.py in any way?
Try deleting the migrations and the database again after ensuring that your models are valid, then run manage.py makemigrations appname and then manage.py migrate.
You could try:
Deleted everything in the django-migrations table.
Deleted all files in migrations folder and then run python manage.py makemigrations followed by python manage.py migrate as you said.
If this doesn't work, try:
Deleted everything in the django-migrations table.
Deleted all files in migrations folder, use your old model.py to run python manage.py makemigrations followed by python manage.py migrate.
Add new model, run python manage.py makemigrations followed by python manage.py migrate again.

Reset SQLite database in Django

I am trying to refactor a Django project. I renamed a couple apps and added a new one, as well as shuffled some models around. I want to clear my database and migrations and start fresh, but I am not sure how to accomplish this. Here's what I did:
rm -r myapp/migrations // I ran this for all my apps
python manage.py flush
python manage.py makemigrations myapp // I ran this for all my apps
python manage.py migrate // This errors
I get an error:
django.db.utils.OperationalError: table "myapp_mymodel" already exists
Can anyone tell me what I might be doing wrong?
EDIT: What is the django command to delete all tables? did not work.
Delete database and delete migration files (.py and .pyc) in migrations directory of your app (don't delete __init__.py file). Then run python manage.py makemigrations app and python manage.py migrate.
I had the same issue, using Django 1.10, here is what I did, I deleted the database sqlite file, deleted the pycache folders inside each of the apps, deleted all files inside the migrations folder for each app , except the init.py file, and then ran python manage.py makemigrations and python manage.py migrate. Also note that because you deleted the database you will have to create a new superuser using python manage.py createsuperuser. Hope this helps
For me, just
python manage.py flush
deleted old db contents, so i was able to create records anew in Django 2.1.4.
Don't forget to create new superuser:
python manage.py createsuperuser
This may help you if you want to clear sqlite3 DB follow these steps.
Delete migrations files except init.py
Delete dbsqlit3 file
Then type python/python3 manage.py migrate
Then make changes in your models
Type python/python3 manage.py makemigrations
Type python/python3 manage.py migrate
Then you have to create new superuser by just typing python/python3 manage.py createsuperuser . you should use new name not old user name
Do not delete your database file!
Its correct to delete migration files and then run flush but deleting sqlite database file is wrong. This worked to me every time. If you are using other database, it will save you a lot of work and preparations.
delete all ".py" and ".pyc" files manually
python manage.py flush
type "yes" to confirm
python manage.py makemigrations
python manage.py migrate

Django : Table doesn't exist

I dropped some table related to an app. and again tried the syncdb command
python manage.py syncdb
It shows error like
django.db.utils.ProgrammingError: (1146, "Table 'someapp.feed' doesn't exist")
models.py
class feed(models.Model):
user = models.ForeignKey(User,null=True,blank=True)
feed_text = models.CharField(max_length=2000)
date = models.CharField(max_length=30)
upvote = models.IntegerField(default=0)
downvote = models.IntegerField(default=0)
def __str__(self):
return feed.content
What I can do to get the tables for that app ?
drop tables (you already did),
comment-out the model in model.py,
and ..
if django version >= 1.7:
python manage.py makemigrations
python manage.py migrate --fake
else
python manage.py schemamigration someapp --auto
python manage.py migrate someapp --fake
comment-in your model in models.py
go to step 3. BUT this time without --fake
For those that may still be having trouble (like me), try this out:
Comment out all the URL's in the main app's urls.py
Then go ahead and run migrations:
$ ./manage.py makemigrations
$ ./manage.py migrate
The problem was alleviated by removing the ()'s
solved_time = models.DateTimeField('solved time', default=timezone.now())
to
solved_time = models.DateTimeField('solved time', default=timezone.now)
I got this answer from reddit
What solved my problem in situation when manage.py setmigration and then migrate to the SQL database is not working properly did is following:
Run command : python manage.py migrate --fake MyApp zero
After that: python manage.py migrate MyApp
And the problem that rises with connections.py and and after running correctly the migration command is solved! At least for me.
I'm using Python (3.x), MySQL DB, Django (3.x), and I was in situation when I needed after some time of successfully creating tables in my database, that some error regarding connections.py raises. But, above commands helped. I hope they will help all those who are having these type of problems.
I just ran migrations with the name of the app attached, for all the apps I had provisioned and that worked.
e.g. python3 manage.py makemigrations my_custom_app
After running for all of them I ran a migrate command to seal the deal.
python3 manage.py migrate. That was it. I'm still wondering why django behaves this way sometimes though.
none of the above solutions worked for me, I finally solved by
sudo systemctl stop mysql.service
sudo apt-get purge mysql-server
sudo apt-get install mysql-server
sudo systemctl stop mysql.service
In my case the code that I pulled had managed = False and I wanted the tables to be maintained by Django.
But when I did makemigrations the custom tables were not being detected or I was getting the error that the app_name.Table_name does not exist
I tried the following:
delete all the migration files inside the migrations folder (except init.py file) and then makemigrations then finally migrate
above 2 answers
this
PS: This solution is only feasible if backup is present or data is not important or you are just started creating the tables, as purging mysql will lead to loss of data
This is linked to the migration data in the scripts inside the project not matching with the migration scripts in the database as far as I could tell.
I solved this by the following steps :
Delete all the migration scripts under migration folder except __ini__
Make sure that the model.py contains the same structure as the table in the database and managed=True
Remove all Django Created tables like auth_user,... etc
Run the following code
$ ./manage.py makemigrations
$ ./manage.py migrate
This will create the migration scripts again and will apply it to your database.
I had this issue where I was playing with same database structure in production vs development. While dropping and recreating tables will probably resolve the issue, its worth checking your database itself and see if the model is actually correct. For myself I created the development database incorrectly with the table names all in lowercase while in production the first letter of tables were capitalized. I used the python manage.py inspectdb command on production db, and compared it to the model and realized that in the model it was trying to insert data to table 'test' instead of 'Test' for example. Hope that helps some of you in future.
I had a similar issue.
I had another python (with a class) file which need access to DB.
For some reasons, when running 'makemigrations' this file was processed (I guess this is linked to some import chains).
In this class, I had a method containing a default arg method(defaultModel=Model.get_default()) in the signature which was accessing to the default object in the DB (static method included in the Model class).
A the import time, this default arg was evaluated and as the table is not populated yet, it gives this error.
So I just set None for the default args and asks for the default model object inside the method. This solved the issue.
I have to face same issue and there are a couple of approaches, but the one I think is the most probable one.
Maybe you are loading views or queries to database but you havenĀ“t granted enough time for Django to migrate the models to DB. That's why the "table doesn't exist".
Make sure you use this sort of initialization in you view's code:
Class RegisterForm(forms.Form):
def __init__(self, *args, **kwargs):
super(RegisterForm, self).__init__(*args, **kwargs)
A second approach is you clean previous migrations, delete the database and start over the migration process.
I tried all of the above tricks and never worked for me.
I commented on all imports and URLs that called a particular Table
In this solution, your data will be removed. I removed the app and created the app again. I copied the app folder somewhere and delete the app folder from my project. I commented on all lines in urls.py and files similar views.py and admin.py that use this app. also app name in settings.py.
In mysql:
truncate django_migrations;
truncate django_admin_log;
Do this for all models in your app and change n.
n is app id.
delete from auth_permission where content_type_id=n
delete from django_content_type where app_label='appname'
python manage.py startapp your_app_name
Then uncomment previous lines and restore files and run
python manage.py makemigrations
python manage.pt migrate
I faced the same problem, some of the above mentioned answers seemed not to work for me, but here's a simple 4 step solution:
1) Delete the migrations files below __init__.py (don't delete __init__.py) in your specific app.
2) python manage.py makemigrations AppName
3) python manage.py migrate --fake AppName zero
4) python manage.py migrate AppName
Hope these works for you.
I faced the same issue earlier when I accidentally deleted my migrations folder in an app. I was able to fix it by running manual makemigrations for that specific app.
Here's the fix for Windows,
py manage.py makemigrations <your_app_name>
py manage.py migrate
For other OS you need to replace py with python3 or python
I hope this helped fix your issue!
if the python manage.py migrate still doesn't work I mean when you do this it nothing do anything you can delete the app's migrations from django_migrations table after then do
python manage.py migrate

Django Error: OperationalError: no such table: polls_poll

Going through Django tutorial 1 using Python 2.7 and can't seem to resolve this error:
OperationalError: no such table: polls_poll
This happens the moment I enter Poll.objects.all() into the shell.
Things I've already tried based on research through the net:
1) Ensured that 'polls' is listed under INSTALLED_APPS in settings.py
Note: I've seen lots of suggestions inserting 'mysite.polls' instead of 'polls' into INSTALLED_APPS but this gives the following error: ImportError: cannot import name 'polls' from 'mysite'
2) Run python manage.py syncdb . This creates my db.sqlite3 file successfully and seemingly without issue in my mysite folder.
3) Finally, when I run python manage.py shell, the shell runs smoothly, however I do get some weird Runtime Warning when it starts and wonder if the polls_poll error is connected:
\django\db\backends\sqlite3\base.py:63: RuntimeWarning: SQLite received a naive datetime (2014-02-03 17:32:24.392000) while time zone support is active.
Any help would be appreciated.
I meet the same problem today and fix it I think you miss some command in tutorial 1 just do follow:
./python manage.py makemigrations polls
python manage.py sql polls
./python manage.py syncdb
then fix it and gain the table polls and you can see the table created you should read the "manage.py makemigrations" command
i figured out the mistake you did, after making changes to your models.py you should run migrate ..i.e
python manage.py migrate
then only your changes(polls_question) will be visible
For those encountering this error in the current django 3.0 release (https://docs.djangoproject.com/en/3.0/intro/tutorial02/), you can rectify it by making sure you've run the following commands in order.
python manage.py makemigrations polls
python manage.py sqlmigrate polls 0001
python manage.py migrate
I've just solved this problem in a very easy and effective way.
This error is coming because of wrong pycache and db.sqlite3 in django
To solve this error we can delete those files and re-make it.
Delete pycache and db.sqlite3 manually.
then run this in terminal:
python manage.py makemigrations polls
After this your database and __pycache will be created again. And just make migrations, it will work fine.
Of course you might want to store your data before deleting database.

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