As the title suggests, I am interested in how can I create the same model in multiple databases. I have the following scenario: every user has his own database (this is the simplified case) and when the user adds a new module to his app, I want to be able to create the db table for the module that he added.
The idea that I currently have is to create dynamic models, add custom app_label, and than use a Database Router that creates the model in the corresponding database.
Is there an easier way to obtain this?
Thanks in advance!
You should look at the syncdb command - you can call it programmatically like so:
from django.core.management import call_command
call_command('syncdb')
In your case, you'll want to use named arguments for any options you would have passed in at the command line:
call_command('syncdb', noinput=True, database=user_db)
Hope that helps.
Check this out also: https://docs.djangoproject.com/en/dev/ref/django-admin/#running-management-commands-from-your-code
Use the migrate command with different arguments. For instance if your db aliases are primary and secondary
do this
python manage.py migrate --database=primary
python manage.py migrate --databases=secondary
Related
I have an application in Django 2.0 and as a database engine I use MySQL. I have a problem because the database was previously created and already has records, my idea is to use this same database for the application I am creating.
Use the command
python manage.py inspectdb > models.py
To create the models.py file which will be cleaned as indicated by the models.py file that was generated.
#This is an auto-generated Django model module.
# You'll have to do the following manually to clean this up:
# * Rearrange models' order
# * Make sure each model has one field with primary_key=True
# * Make sure each ForeignKey has `on_delete` set to the desired behavior.
# * Remove `managed = False` lines if you wish to allow Django to create, modify, and delete the table
# Feel free to rename the models, but don't rename db_table values or field names.
After this I proceed to execute:
python manage.py migrate
python manage.py makemigrations
python manage.py migrate
But it generates the following error:
(1050, "Table 'XXXXXXX' already exists")
Obviously it tells me that the table already exists, but how do I not generate this error and continue administering the tables from Django.
You need to run --fake-initial or --fake. See more at Django migrations. Be careful because running inspectdb doesn't solve all your problems. You need to fix the things inside models.py manually and migrate again.
One of the things (and the main reason I do not use Django) is it likes to take control of everything. The fact that it controls the database means that if you don't start strictly in Django, you are doing it wrong.
However there is a work around:
https://docs.djangoproject.com/en/2.0/howto/legacy-databases/
In my django application (django 1.8) I'm using two databases, one 'default' which is MySQL, and another one which is a schemaless, read-only database.
I've two models which are accessing this database, and I'd like to exclude these two models permanently from data and schema migrations:
makemigrations should never detect any changes, and create migrations for them
migrate should never complain about missing migrations for that app
So far, I've tried different things, all without any success:
used the managed=False Meta option on both Models
added a allow_migrate method to my router which returns False for both models
Does anyone have an example of how this scenario can be achieved?
Thanks for your help!
So far, I've tried different things, all without any success:
used the managed=False Meta option on both Models
That option (the managed = False attribute on the model's meta options) seems to meet the requirements.
If not, you'll need to expand the question to say exactly what is special about your model that managed = False doesn't do the job.
I thought, I have a problem with makemigrations. It pretends to make migration on managed = False model, but no SQL code generated for this model
Here is my example, model Smdocumets unmanaged, and no SQL code was generated.
python manage.py makemigrations
Migrations for 'monitor':
monitor\migrations\0005_auto_20171102_1125.py
- Create model Smdocuments
- Add field sid to db
- Alter field name on db
python manage.py sqlmigrate monitor 0005
BEGIN;
--
-- Create model Smdocuments
--
--
-- Add field sid to db
--
ALTER TABLE "monitor_db" RENAME TO "monitor_db__old";
...
You have the correct solution:
used the managed=False Meta option on both Models
It may appear that it is not working but it is likely that you are incorrectly preempting the final result when you see - Create model xxx for models with managed = False when running makemigrations.
How have you been checking/confirming that migrations are being made?
makemigrations will still print to terminal - Create model xxx and create code in the migration file but those migrations will not actually result in any SQL code or appear in Running migrations: when you run migrate.
I'm trying to create a database view from django instead of associate a model from an existing database table. I'm new in django world and i don't know how how can i do this. Anyone have any ideia where to start look to solve this? Maybe this is not possible but can you see any alternative solution?
I understand how to define a model that as no management, by consider managed=False like i found on django docs, but how can i create an customized SQL view in my model class?
something like this:
Class myModel(models.Model):
Object = models.raw("CREATE VIEW foo AS SELECT * FROM table.A")
class Meta:
db_table = 'myview\".\"mymodeltable'
managed = False
With inspectdb management command, you can obtain the models definition from existing tables. To do that, you need to configure your settings.py file to have access to the database you want to work with and then do:
python manage.py inspectdb > models.py
You will see that it also automatically sets the managed=False. From that point, you can start querying its objects with typical objects.all(), objects.filter() and this stuff
Note: Don't forget to add the app with the imported models to the INSTALLED_APPS variable of your settings.py file.
Unfortunately maybe this is the final answer that can be found on DjangoDocs
This is useful if the model represents an existing table or a database view that has been created by some other means.
I am trying to add two additional profile fields and have the native authentication work like normal.
I am trying to fallow the documentation here
and the SO here
In my settings file
#settings.py
AUTH_USER_MODEL = 'users.User'
in my users.user model
#users/models.py
from django.contrib.auth.models import AbstractUser
from django.db import models
class User(AbstractUser):
foo = models.CharField(max_length=32, default='Blue')
bar = models.CharField(max_length=32, default='Blue')
print "user.user"
i have created 3 superusers non can log into admin. i have tried syncing the DB after adding a user. i have tried restating the dev server between adding a user.
the only time i see the output of print "user.user" is when i run the createsuperuser command.
i think i cant log in because the user is not really being created. it runs my User class and then skips actually creating the user. but i am kinda new to this so i could be way off and way out of my league.
why cant i log in and how do i add the two fields?
Have you read the warning in Django's documentation?
Changing AUTH_USER_MODEL has a big effect on your database structure. It changes the tables that are available, and it will affect the construction of foreign keys and many-to-many relationships. If you intend to set AUTH_USER_MODEL, you should set it before running manage.py syncdb for the first time.
If you have an existing project and you want to migrate to using a custom User model, you may need to look into using a migration tool like South to ease the transition.
Given this warning, are you working on a fresh database, or are you migrating using South? If you have an existing database and made these changes, then simply running syncdb will most likely no be sufficient.
If this is a development server without any important data, I would recreate your database, and then run ./manage.py syncdb. If you are using a SQLite database, then you can simply copy it to somewhere else (if you would like to keep the data), and run syncdb again to create a new database.
Here is the relevant documentation.
It would also be helpful to know exactly what error you are receiving. Do you attempt to login and admin tells you that your user/pass combination is not correct, or is there an actual error thrown? Your question doesn't quite make this clear.
I created a table before I code the Django app and now I merged both the app and the table with following command python manage.py inspectdb > models.py. However after some while I really need to change the value type of one of the column. Is it enough to chage it through the model file or do I need some additional steps?
If you change a field in a Django model, Django itself doesn't know how to update your database accordingly (syncdb only add tables from new models).
You have two options:
manually create your database tables;
use a migration tool like South that detects and generates migration files from changes made to your models;
I recommend the second option as it's programmatic, more error-proof and makes your life easier when you need to go back and forth between database schemas.
There is an easy way to do this. (in Django 2)
After making the necessary changes to the model.py file of your app, run command:
python manage.py makemigrations - This will generate a new file in migration folder of your app.
python manage.py migrate - This will apply those edits on actual databse.
To check if the changes have been applied, run command : .schema <tablename> in your terminal, after entering the sqlite command-line program.