To use an existing database in Django, you need to have a model for each table. But creating models for existing tables manually is just too much work. However, there's no need to do that, since Django has a builtin tool to solve this exact problem.
Reference article linked here: how-to-integrate-django-with-existing-database
Edit settings.py
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql',
'NAME': '<name>',
'USER': '<user>',
'PASSWORD': '<password>',
'HOST': '<host>',
'PORT': '<port>',
}
}
Generate models for linked existing database tables.
python manage.py inspectdb > models.py
Tweak your tables according to your preferences. Copy all tables and add them to your app models.py
Now create initial migrations for existing tables
python manage.py makemigrations
Run the migrate command to apply the migrations, Use --fake-initial option that applies the migrations where it's possible and skips the migrations where the tables are already there:
python manage.py migrate --fake-initial
At this point, any new changes to the model structure and subsequent migrations would work as if Django managed the database since its inception
Thanks to: Dima Knivets
Related
I have created a project using Golang. I have used PostgreSQL as the database. Now I want to make an admin panel for this project using Django. I want directly reflect the database tables in the Django admin panel. As I am not running the project under the Django server and I don't have any apps and models, how can I show them in the admin panel?
What you want is to use an existing DB to be managed by the DJango admin. To do this you must create a django project and create the models for each table. This is very tedious so there is an official process so you don't have to do all this work and it is done automatically.
$ python manage.py inspectdb
https://docs.djangoproject.com/en/4.1/howto/legacy-databases/
First create an empty project in django then in settings.py set your database as postgreSQL
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql',
'NAME': 'customers',
'USER': 'root',
'PASSWORD': '',
'HOST': 'localhost',
'PORT': '5432',
}
}
make sure to create superuser for login in admin panel and proper urls for the same.
Add models in models.py and register it in admin.py
P.S - make sure you have installed psycopg2 using pip command.
I just deploy my Django app to Heroku but I cant migrate my migrations to heroku. First I run :
heroku run python manage.py migrate all the migrations list as OK but when I showmigrations, none of them is migrating (all blank [ ]).
Then I try heroku run bash and migrate from there, everything seems ok even showmigrations from bash showing all of the migrations is working. I even manage to create a superuser. But when I open my admin page and log in with superuser it shows 'account.account' table does not exist and when I check showmigrations again all of the migrations are gone. I have been repeating this migration over and over and still can't figure this out.
Does anyone know what I am doing wrong here?
Edit :
I don't know if this is related but when I push my project to Heroku the first time, I'm using Postgre with this setting :
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql_psycopg2',
'NAME': DB_NAME,
'USER': DB_USER,
'PASSWORD': DB_PASSWORD,
'HOST': 'localhost',
'PORT': '5432',
}
}
but when I try to run migrations it shows an error something like cant access localhost with 5432 port, it turns out that Heroku trying to access postgre in my localhost instead of using Heroku Postgres. The solution I found is to dump my db and reload it to Heroku. And since I don't know how to set that up. I just comment that postgre setting and replace it with default django setting :
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': BASE_DIR / 'db.sqlite3',
}
}
create my dbsqlite file, running migrations again then once again push it to Heroku, hoping to find an easy way out but instead ended up in this problem
I'd recommend you to push a migrated project to heroku that is
python manage.py migrate
then push that migrated project to heroku
the reason your superuser doesn't get stored while creating superuser from heroku bash is because heroku has an ephemeral drive i.e heroku clears all the modified data from orignal push after equal interval of time.
It turns out that I forgot to install django-heroku. More on this : https://devcenter.heroku.com/articles/django-app-configuration
I want to deploy my django project to the production environments, and associated it with an new empty database, and I did as follows :
Create an new empty database
Updated settings.py and pointed the database name to the new one
Deleted the migrations folder under my App
Run python manage.py runserver and no errors returned
Run python manage.py makemigrations and python manage.py migrate
but only auth related tables created ( like auth_user , auth_group ... ), no databases tables created for my Apps
How should I do for this situation to move to the new database for my project?
Deleted the migrations folder under my App
This was your mistake, you deleted the migrations - including the initial migrations. So when you go to makemigrations you haven't got the initial migration available.
So you need to run makemigrations <app_name> to at least get the initial migration.
If you were to do this again, don't delete the migrations, just change the database settings and then migrate.
Firstly, you should not have deleted the migrations. Now, make all the migrations again which you have deleted.
python manage.py makemigrations app_name
Do this for all the apps of which you have deleted the migrations.
Now, add your new database to settings.py. Do not remove the old one yet. For example, if I were adding a MySQL database, I would have added the following to the DATABASES dictionary in settings.py:
'new': {
'ENGINE': 'django.db.backends.mysql',
'NAME': 'databasename',
'USER': 'databaseusername',
'PASSWORD': 'databasepassword',
'HOST': 'localhost',
'PORT': '3306',
}
I have named the database as 'new'. Now we have two databases 'default' and 'new'. Now you have to create tables in the new database by running the migrations on the new database:
python manage.py migrate --database=new
You can follow these additional steps if you want to transfer your data to the new database. First, clear the new database:
python manage.py flush --database=new
Now export data from the old database into a json file:
python manage.py dumpdata>data.json
Import this data into the new database:
python manage.py loaddata data.json --database=new
Now you can remove the 'default' database and rename the 'new' database to 'default'.
The procedure mentioned in this answer is taken from my blog.
Just check the output of python manage.py makemigrations command, if it is showing no change detected then you need to check that have you added that app in your INSTALLED_APPS = [] in settings.py file or it might be the problem because you have deleted migration folder.Because if is there any database connectivity error it will show you that while doing makemigrations.
If your database has a new name, i.e. not "default", you need to specify it to migrate:
python manage.py migrate --database <newdb>
I have the following database settings in Mezzanine:
DATABASES = {
"default": {
'ENGINE': 'django.db.backends.postgresql_psycopg2',
'NAME': 'lucidDB',
'USER': 'lucid',
'PASSWORD': 'xxxxxxxx',
'HOST': 'localhost',
'PORT': '',
}
}
I run the command python manage.py createdb and then answer yes to the question Would you like to fake initial migrations? (yes/no):.
Note: south was installed.
My questions:
I checked in postgres (postgres# psql --> postgres=# \l), but didn't find the database lucidDB. However, the system runs OK. Where exactly is the database created?
What does it mean by fake migration?
I didn't run syncdb or makemigrations --> migrate yet, why the system worked?
You didn't find the LucidDB in postgres because it wasn't created, you need to create it with the postgres shell see here for detailed description.
Faking a migration is marking it as complete without actually changing the database schema, it will simply add an entry in the migrationhistory database, see detailed description here.
On the Mezzanine docs it is stated that createdb is a shortcut for syncdb and migrate commands, see here for detailed description.
Hope this helps!
i'm using django 1.3. i have an existing oracle database (10g) i would like to build Model's from using inspectdb.
'db': {
'ENGINE': 'django.db.backends.oracle',
'NAME': 'DBNAME',
'USER': 'me',
'PASSWORD': 'something',
}
so when run inspectdb i get:
$ python manage.py inspectdb --database db
cx_Oracle.InterfaceError: Unable to acquire Oracle environment handle
so i add
$ export ORACLE_HOME=/usr/oracle/
$ TWO_TASK=DBNAME
i try logging on with sqlplus with the same credentials and everything looks good.
so... i run inspectdb again, but this time i get
# 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
# Feel free to rename the models, but don't rename db_table values or field names.
#
# Also note: You'll have to insert the output of 'django-admin.py sqlcustom [appname]'
# into your database.
from django.db import models
(ie it's blank)
any ideas? i had no problems getting this to work on a mysql database.
From the official docs.
inspectdb works with PostgreSQL, MySQL and SQLite. Foreign-key detection only works in PostgreSQL and with certain types of MySQL tables.
There is currently not a bug listed for it in the Django tracker if you wanted to submit it.
I have a similar setup at the top of my settings.py to set my environment variables for my oracle driver (Oracle 11.2). Not sure if this will help in your specific case.
### SETTING UP THE ENVIRONENT FOR OUR ORACLE RPM
import os
os.putenv('ORACLE_HOME', '/.../oracle/11.2')
os.putenv('LD_LIBRARY_PATH', '/.../oracle/11.2/lib')
I have had no issues with manage.py inspectdb (Django 1.2.7 and Django 1.4) on Oracle 11.2.