Multiple Databases --Migrations - python

I am using 2 postgres databases in my django app.
'newpostgre': {
'ENGINE': 'django.db.backends.postgresql_psycopg2',
'NAME': 'new_postgre2',
'USER': 'tester',
'PASSWORD': 'password',
'HOST': 'localhost',
'PORT': '',
},
'newpostgre2': {
'ENGINE': 'django.db.backends.postgresql_psycopg2',
'NAME': 'new_postgre3',
'USER': 'tester',
'PASSWORD': 'password',
'HOST': 'localhost',
'PORT': '',
},
I have a very simple model
class Check1(models.Model):
title = models.CharField(max_length=100)
I had run
python manage.py migrate --database=newpostgre
python manage.py migrate --database=newpostgre2
when I open my new_postgre2(for newpostgre) database in postgre, I can see my Check1 table there.
But in my new_postgre3(for newpostgre2) database in postgre, no Check1 table is there, only those initial migrations are there.
Why I can't see my table in new_postgre3 when migrations have been successfully made?

Because The same object name can be used in different schemas sometimes conflict. The best practice allow many users to use one database without interfering with each other. Use this change second database user and check again. I think it is work.
'newpostgre': {
'ENGINE': 'django.db.backends.postgresql_psycopg2',
'NAME': 'new_postgre2',
'USER': 'tester',
'PASSWORD': 'password',
'HOST': 'localhost',
'PORT': '',
},
'newpostgre2': {
'ENGINE': 'django.db.backends.postgresql_psycopg2',
'NAME': 'new_postgre3',
'USER': 'tester_different',
'PASSWORD': 'password_different',
'HOST': 'localhost',
'PORT': '',
},
python manage.py migrate --database=newpostgre2

Related

django.db.utils.OperationalError: FATAL: database "clinilead_e " does not exist

After changing the db from sqlite to postgresql(python manage.py makemigrations)running, I am getting this error.How could i overcome this?
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql_psycopg2',
'NAME': 'clinilead_e ',
'USER': 'postgres',
'PASSWORD': 'password',
'HOST': '127.0.0.1',
'PORT': '5432',
}
}
In postgres, unlike sqlite you have to create the database.
$ createdb clinilead_e

Is need to change DB in unit test cases - python django

I am creating unit test cases now.. I create delete API.. Its working fine with Post Man. Its delete the the Record... But Its do not delete Report when I run this in test case.. Its wrong something or its normal behaviour in test cases. I am creating this test cases in python..
Thanks in Advance
As i remember, you can add multiple connections in settings.py file
DATABASES = {
'default': {
'ENGINE': 'django_tenants.postgresql_backend',
'NAME': 'db_prod',
'USER': 'user',
'PASSWORD': 'pass',
'HOST': 'http://example.com',
'PORT': '5432',
},
'test': {
'ENGINE': 'django_tenants.postgresql_backend',
'NAME': 'db_test',
'USER': 'user',
'PASSWORD': 'pass',
'HOST': 'http://example.com',
'PORT': '5432',
}
}
Then use it on model like this Model.objects.using('test')

Running two databases on heroku with django

I have two databases that my Django application needs access. One is a shared database owned by a separate app with the Django app only having read access. The second is entirely owned by the Django app.
For local development I am ok but I'm not sure how to configure things so that Heroku uses the second database.
Currently I have the shared database promoted to DATABASE_URL and the secondary database is at HEROKU_POSTGRESQL_BLUE_URL.
In my settings I have:
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql',
'NAME': 'main_database_name',
'USER': 'username',
'PASSWORD': '',
'HOST': 'localhost',
'PORT': '5432',
}, 'secondary': {
'ENGINE': 'django.db.backends.postgresql',
'NAME': 'secondary_database_name',
'USER': 'username',
'PASSWORD': '',
'HOST': 'localhost',
'PORT': '5432',
}
}
Please ask any more questions if you need me to clarify.
Thanks!
In summary, my specific problem is: I don't know how to have Heroku use the HEROKU_POSTGRESQL_BLUE_URL as the "secondary" database.
---Edit----
At the bottom of settings.py:
# Configure Django App for Heroku.
import django_heroku
django_heroku.settings(locals())
This is where the connection is made between my app's default database and Heroku's DATABASE_URL. I still haven't solved the issue but after some troubleshooting help in the comments, I believe the answer will be found in there.
Here is my working solution.
I have a local_settings.py file not tracked by version control. This contains the database settings for the developer's postgres instance.
local_settings.py
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql',
'NAME': 'main_database_name',
'USER': 'username',
'PASSWORD': '',
'HOST': 'localhost',
'PORT': '5432',
}, 'secondary': {
'ENGINE': 'django.db.backends.postgresql',
'NAME': 'secondary_database_name',
'USER': 'username',
'PASSWORD': '',
'HOST': 'localhost',
'PORT': '5432',
}
}
Then in settings.py I try to import the local_settings.py file. If it doesn't exist, I use the django_heroku package to configure everything for Heroku. In my case, I need to pass the keyword argument databases=False since I want to do a more custom configuration for the databases.
settings.py (only the relevant parts)
# Database
# https://docs.djangoproject.com/en/2.0/ref/settings/#databases
# These database settings are used for heroku deployments. They are overwritten with local_settings.py in development.
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql',
'NAME': os.environ.get('DATABASE_URL'),
'USER': '',
'PASSWORD': '',
'HOST': 'localhost',
'PORT': '5432',
}, 'secondary': {
'ENGINE': 'django.db.backends.postgresql',
'NAME': os.environ.get('SECONDARY_DATABASE_URL'),
'USER': '',
'PASSWORD': '',
'HOST': 'localhost',
'PORT': '5432',
}
}
try:
from local_settings import *
except ImportError as e:
# Configure Django App for Heroku.
import django_heroku
django_heroku.settings(locals(), databases=False)
In order for this to work you would need to set the Heroku env variable SECONDARY_DATABASE_NAME to the url of your database.
To find out the URL of your secondary database run heroku config -a your_app_name. Copy the url and then set a new environment param in heroku by running
heroku config:set SECONDARY_DATABASE_URL=postgres://xxxxxxx -a your_app_Name
There are a lot of choices with how you would handle the ENV variables, I liked this because I can just set it in my staging and production environments and the same settings work for both.

Cannot overwrite default django database settings

I've got a problem with Django DATABASES setting in settings.py.
I'm using Python 3.4.3, Django 1.10.5 and psycopg 2.6.1
if my code looks like
DATABASES = {
'default':{
'ENGINE': 'django.db.backends.postgresql_psycopg2',
'NAME': ' dbname',
'USER': 'postgres',
'PASSWORD': 'dbpass',
'HOST': 'localhost',
'PORT': '5432',
}
}
and i run manage.py diffsettings in DATABASE section there are some default settings:
DATABASES = {'default': {'USER': '', 'HOST': '', 'AUTOCOMMIT': True, 'NAME': '', 'ATOMIC_REQUESTS': False, 'OPTIONS': {}, 'TEST': {'MIRROR': None, 'CHARSET': None, 'NAME': None, 'COLLATION': None}, 'ENGINE': 'django.db.backends.dummy', 'PASSWORD': '', 'CONN_MAX_AGE': 0, 'TIME_ZONE': None, 'PORT': ''}}
but when I change 'default' to 'db' (or any other name)
DATABASES = {
'db':{
'ENGINE': 'django.db.backends.postgresql_psycopg2',
'NAME': ' dbname',
'USER': 'postgres',
'PASSWORD': 'dbpass',
'HOST': 'localhost',
'PORT': '5432',
}
}
the manage.py diffsettings 'knows' the database db:
DATABASES = {'db': {'NAME': 'dbname', 'HOST': 'localhost', 'PORT': '5432', 'PASSWORD': 'dbpass', 'ENGINE': 'django.db.backends.postgresql_psycopg2', 'USER': 'postgres'}, 'default': {'OPTIONS': {}, 'ATOMIC_REQUESTS': False, 'HOST': '', 'AUTOCOMMIT': True, 'PASSWORD': '', 'USER': '', 'TIME_ZONE': None, 'NAME': '', 'PORT': '', 'CONN_MAX_AGE': 0, 'ENGINE': 'django.db.backends.dummy', 'TEST': {'NAME': None, 'MIRROR': None, 'COLLATION': None, 'CHARSET': None}}}
What should I to to use my database as a default and don't have to use DATABASE_ROUTERS ?
From your comment in the question above, I'm assuming that you're trying to set up Django in a Heroku instance.
If you're using Heroku's starter template, you're going to see an overwrite to the DATABASES variable. This is because Heroku uses the library dj_database_url to get the environment path of the database that was deployed with your Heroku app. So Django updates the default database to use it. This is relevant when you want to deploy your Django app to the Heroku instance.
In case you want to use your app in your local environment (your machine), you just need to comment those two lines:
# db_from_env = dj_database_url.config(conn_max_age=500)
# DATABASES['default'].update(db_from_env)
But remember to comment out those lines again when uploading your code to Heroku.

Want to implement multiple database in django project

I want to use multiple sqlite3 database for my app. I want to write some of the data(which is user log) to one database and rest of the stuff to another db. After that I want to read from both the database.
Thanks
DATABASE_ROUTERS = ['manager.router.DatabaseAppsRouter']
DATABASE_APPS_MAPPING = { 'db_b':'db_b'}
DATABASES = {
'default': {
'ENGINE': 'backend_of_your_choice',
'NAME': 'default',
'USER': 'xxx',
'PASSWORD': 'xxx',
'HOST': '127.0.0.1',
'PORT': '',
},
'db_b': {
'ENGINE': 'backend_of_your_choice',
'NAME': 'db_b',
'USER': 'xxx',
'PASSWORD': 'xxx',
'HOST': '127.0.0.1',
'PORT': '',
},}
Then in your model MetaClass define the following for all the models which you want to use db_b:
class Meta:
app_label = 'db_b'

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