Why should we use three migration commands to migrate our database succesfully? - python

I was working on models in django and after creating classes for models and when migrating them I was supposed to use three commands for completing migration of models. The commands are :python manage.py migrate,python manage.py makemigrations <app_name>,python manage.py migrate
So my question is that why should we use three commands like this ?

From the django docs,
migrate: which is responsible for applying and unapplying migrations.
makemigrations: which is responsible for creating new
migrations based on the changes you have made to your models.
If you make changes to your model use python manage.py makemigrations followed by python manage.py migrate.
Incase of initial migration just after you create an app you dont need to python manage.py makemigrations but just python manage.py migrate works.

Related

Django models does not create table after I clone it on github

Recently I'm doing a small Django project that I have to work with my teammates,
so I clone the project's repository from github.
The problem is , the database in my computer doesn't have the table so i think i have to makemigrations and migrate it. But after i did that,django only createed its own tables but didn't create other tables that my teammates wrote in Django's models.
I really need your guys hlep
this are the models my teammates wrote
but after i makemigrations and migrate it ,phpmyadmin does not show the tables i want
makemigrations and migrate
the picture on phpmyadmin after I migrate django models
This is my settings
after tried this,it still not working
migrations folder
You should use managed=True in all models for managing the migrations via django
run
python manage.py makemigrations *name_of_you_app_that_has_models_here*
python manage.py migrate *name_of_you_app_that_has_models_here*

Migrate two different models from two different Django applications

Hi guys so i have a Django project with two application named, shopper, parcel, each of this app have one model also named Parcel and Shopper. there is a one-to-many relationship between the 2 models. the problem is i want to migrate the two models, if I was just one i could have gone with the normal way of migrating a model.
This is what i have tried
python manage.py makemigrations parcel
python manage.py migrate
the problem with the first one is it does not take the other models in the shopper app into consideration and that is not what i want.
python manage.py makemigrations parcel
python manage.py migrate
python manage.py makemigrations shopper
python manage.py migrate
this was my second solution, the commands end up creating migration of each model but still i don't think that is the right thing to do.
Any help in the right direction please

When I make migrations to Django, all accounts are deleted

When I enter the commands python manage.py makemigrations and python manage.py migrate all accounts are deleted from the database. Perhaps the database is simply re-created
UPD. Screenshot
Hi #AleRyp and welcome to stackoverflow.
Usually
./manage.py makemigrations
does nothing unless you don't have changes in your models.
Instead
./manage.py migrate
does something only there're new migrations to be applied.
Would be nice to see the output of both commands in your case

Django migrating app without migrations

I've created a new Django project consisting of a single app. I thought Django would only migrate an app only if its migrations exist.
The first time I run python manage.py migrate, Django would create tables for my app as well(I've created models.py for my app)
I haven't run python manage.py makemigrations app or python manage.py makemigrations till this time.
I would get the following output on running python manage.py migrate:
Synchronizing apps without migrations:
Creating tables...
Creating table app_model
This is not what I want, because the next time I actually make migrations for the app and run migrate, Django would complain that the tables already exist.
You can create the migrations, and fake the first migration:
python manage.py makemigrations <app_name>
python manage.py migrate --fake-initial
This will skip any initial migration for which the tables have already been created.
Django (pre 1.9) will synchronize any apps that don't have migrations, see the docs on migrate:
The behavior of this command changes depending on the arguments provided:
No arguments: All migrated apps have all of their migrations run, and all unmigrated apps are synchronized with the database,
If you want to save migrations for app, wich you already migrate. You can change one field in model, then makemigrations this_app -> migrate and return has been again with makemigrations and migrate. But I dont understand why you want this.

What should I use instead of syncdb in Django 1.9?

Take a look at this:
$ pypy ./manage.py syncdb
/usr/lib64/pypy-2.4.0/site-packages/django/core/management/commands/syncdb.py:24: RemovedInDjango19Warning: The syncdb command will be removed in Django 1.9
warnings.warn("The syncdb command will be removed in Django 1.9", RemovedInDjango19Warning)
(cut)
I ran a quick google search, but could not find the answer - what should I be using instead of syncdb?
syncdb is deprecated because of the migration system, introduced with django 1.7.
Now you can track your changes using makemigrations. This transforms your model changes into python code to make them deployable to another databases. When you have further modifications you need applied to the database, you can use data migrations.
After you created the migrations you have to apply them: migrate.
So instead of using syncdb you should use makemigrations and then migrate.
Workflow on development after you changed something in your models:
./manage.py makemigrations
./manage.py migrate
And on your production system:
./manage.py migrate
Bonus: you do not need to run migrate for each change. If you have multiple changes not applied yet django will run them in the correct order for you.
You should definitely use migration system. Which lets you track changes in your models.py, and create migrations for the database. The migration system uses the commands makemigrations to create migrations and migrate to migrate the database.
If for whatever reason you need to create a database the same way syncdb did it there is command flag that causes migrate to work the same way. You should only do this if you REALLY need it and you know what you are doing. For example to create an empty database on for a continuous integration system of your choice.
python manage.py migrate auth
# performs migrations for auth and contenttypes contrib apps
python manage.py migrate --run-syncdb
# creates the rest of the database
Tested on Django 1.9.1.
You should use the makemigrations and migrate commands that were introduced in django 1.7
https://docs.djangoproject.com/en/1.7/topics/migrations/
syncdb has some problem with db migration. so, after django 1.7 makemigrations and migrate have been introduced.
Now in django 1.9 syncdb has been deprecated.
try
1. python manage.py makemigrations which detects changes in db and creates one .py file as inside migrations folder
2. python manage.py migrate will apply the migrations to the database

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