How do I manage a Non-default Django PostgreSQL database
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Stephen M
Apr 8, 2015, 8:53:11 PM4/8/15
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Also posted to stackoverflow: How do I manage a Non-default Django database
I am having trouble using my non-default database in my Djaango (v1.8) app. When I
try makemigrations and migrate the PostgreSQL database does not get updated.
Here is my Django structure:
fbrDjangoSite
|-- db.sqlite3
|-- manage.py
|-- fbrDjangoSite
| |-- __init__.py
| |-- requirements.txt
| |-- settings.py
| |-- urls.py
| |-- wsgi.py
|-- fbrPostHasteAppV0_1
| |-- __init__.py
| |-- admin.py
| |-- migrations
| |-- models.py
| |-- router.py
| |-- tests.py
| |-- urls.py
| |-- views.py
# fbrPostHasteAppV0_1/admin.py
from django.contrib import admin
from fbrPostHasteAppV0_1.models import MusicianTable # gvim ../fbrPostHasteAppV0_1/models.py +/MusicianTable
from fbrPostHasteAppV0_1.models import AlbumTable # gvim ../fbrPostHasteAppV0_1/models.py +/AlbumTable
# Register your models here.
admin.site.register(MusicianTable)
admin.site.register(AlbumTable)
# fbrPostHasteAppV0_1/models.py
from django.db import models
# Define your models/tables here.
class MusicianTable(models.Model):
first_name = models.CharField(max_length=50)
last_name = models.CharField(max_length=50)
instrument = models.CharField(max_length=100)
class Meta:
managed = True
class AlbumTable(models.Model):
artist = models.ForeignKey(MusicianTable)
name = models.CharField(max_length=100)
release_date = models.DateField()
num_stars = models.IntegerField()
class Meta:
managed = True
# fbrPostHasteAppV0_1/router.py
class fbrPostHasteAppV0_1Router(object):
def db_for_read(self, model, **hints):
if model._meta.app_label == 'fbrPostHasteAppV0_1':
return 'fbrPostHasteDbV0_1'
return None
def db_for_write(self, model, **hints):
if model._meta.app_label == 'fbrPostHasteAppV0_1':
return 'fbrPostHasteDbV0_1'
return None
def allow_syncdb(self, db, model):
if db == 'fbrPostHasteDbV0_1':
return model._meta.app_label == 'fbrPostHasteAppV0_1'
elif model._meta.app_label == 'fbrPostHasteAppV0_1':
return False
return None
# fbrDjangoSite/settings.py
# ...
INSTALLED_APPS = (
# ...
'fbrPostHasteAppV0_1', # v ../fbrPostHasteAppV0_1/__init__.py
)
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
},
# ...
'fbrPostHasteDb': {
'ENGINE': 'django.db.backends.postgresql_psycopg2',
'NAME': 'fbrPostHasteDbV0_1',
'USER': 'myuser',
'PASSWORD': '',
'HOST': 'myhost.us.overlord.com',
'PORT': '0000',
},
}
DATABASE_ROUTERS = ['fbrPostHasteAppV0_1.router.fbrPostHasteAppV0_1Router',]
Here is the output when I run the migration commands:
[fbrDjangoServerV0_1.venv.py] /<3>django/fbrDjangoServerV0_1.venv.py/fbrDjangoSite> python manage.py makemigrations fbrPostHasteAppV0_1 --verbosity 3
/fobar-tools/pylibs/lib/python/Django-1.8-py2.7.egg/django/db/models/base.py:1497: RemovedInDjango19Warning: Router.allow_syncdb has been deprecated and will stop working in Django 1.9. Rename the method to allow_migrate.
if not router.allow_migrate(db, cls):
Did you rename the fbrPostHasteAppV0_1.Musician model to MusicianTable? [y/N] y
Migrations for 'fbrPostHasteAppV0_1':
0002_auto_20150408_1653.py:
- Create model AlbumTable
- Rename model Musician to MusicianTable
- Remove field artist from album
- Delete model Album
- Add field artist to albumtable
[fbrDjangoServerV0_1.venv.py] /<3>django/fbrDjangoServerV0_1.venv.py/fbrDjangoSite> python manage.py migrate --verbosity 3
/fobar-tools/pylibs/lib/python/Django-1.8-py2.7.egg/django/db/models/base.py:1497: RemovedInDjango19Warning: Router.allow_syncdb has been deprecated and will stop working in Django 1.9. Rename the method to allow_migrate.
if not router.allow_migrate(db, cls):
Operations to perform:
Synchronize unmigrated apps: staticfiles, messages
Apply all migrations: fbrSimDataV0_2, sessions, admin, polls, auth, contenttypes, fbrPostHasteAppV0_1
Synchronizing apps without migrations:
/fobar-tools/pylibs/lib/python/Django-1.8-py2.7.egg/django/db/utils.py:336: RemovedInDjango19Warning: Router.allow_syncdb has been deprecated and will stop working in Django 1.9. Rename the method to allow_migrate.
return [model for model in models if self.allow_migrate(db, model)]
Creating tables...
Installing custom SQL...
Installing indexes...
Running migrations:
Applying fbrPostHasteAppV0_1.0002_auto_20150408_1653.../fobar-tools/pylibs/lib/python/Django-1.8-py2.7.egg/django/db/migrations/operations/base.py:107: RemovedInDjango19Warning: Router.allow_syncdb has been deprecated and will stop working in Django 1.9. Rename the method to allow_migrate.
router.allow_migrate(connection_alias, model) and
OK
/fobar-tools/pylibs/lib/python/Django-1.8-py2.7.egg/django/contrib/auth/management/__init__.py:70: RemovedInDjango19Warning: Router.allow_syncdb has been deprecated and will stop working in Django 1.9. Rename the method to allow_migrate.
if not router.allow_migrate(using, Permission):
The following content types are stale and need to be deleted:
fbrPostHasteAppV0_1 | album
fbrPostHasteAppV0_1 | musician
But when I look at the dtatbase the "table" has not been added.
[fbrDjangoServerV0_1.venv.py] /<3>django/fbrDjangoServerV0_1.venv.py/fbrDjangoSite> psql -h localhost -p 0000 --command "\l" postgres
List of databases
Name | Owner | Encoding | Collate | Ctype | Access privileges
-----------+----------+-----------+---------+-------+-----------------------
postgres | myuser | SQL_ASCII | C | C |
template0 | myuser | SQL_ASCII | C | C | =c/myuser +
| | | | | myuser=CTc/myuser
template1 | myuser | SQL_ASCII | C | C | =c/myuser +
| | | | | myuser=CTc/myuser
test | myuser | SQL_ASCII | C | C |
(4 rows)
I was under the impression that Django could create the table and keep it in
sync whenever I made changes to the model. Is my understanding correct and if
so what am I doing wrong here?
Stephen Meckley
Message has been deleted
Stephen M
Apr 9, 2015, 9:13:06 AM4/9/15
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If Django migrations with PostgreSQL is a bit flaky (as suggested by S.O. comment) which backend database is reliably supported by the Django migrations mechanism?
Carl Meyer
Apr 9, 2015, 11:30:14 AM4/9/15
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database for Django migrations.
I'm not entirely sure what's going on in your example, but the issue is
most likely related to multiple-databases, not related to Postgres. Did
you read the documentation at
http://django.readthedocs.org/en/latest/topics/db/multi-db.html#synchronizing-your-databases
(really you should carefully read that whole page if you're using
multiple databases)? Did you use the `--database` option to the
`migrate` command?
Carl
Stephen M
Apr 9, 2015, 1:34:11 PM4/9/15
to django...@googlegroups.com
# UPDATE
One of my issues is that my router code was based on and older version of
Django. I am not sure if this is exactly correct now but it closely resembles
the documentation now: https://docs.djangoproject.com/en/1.8/topics/db/multi-db/
class fbrPostHasteAppV0_1Router(object):
def db_for_read(self, model, **hints):
if model._meta.app_label == 'fbrPostHasteAppV0_1':
return 'fbrPostHasteDbV0_1'
return None
def db_for_write(self, model, **hints):
if model._meta.app_label == 'fbrPostHasteAppV0_1':
return 'fbrPostHasteDbV0_1'
return None
def allow_relation(self, obj1, obj2, **hints):
if obj1._meta.app_label == 'fbrPostHasteAppV0_1' or \
obj2._meta.app_label == 'fbrPostHasteAppV0_1':
return True
return None
def allow_migrate(self, db, app_label, model=None, **hints):
if app_label == 'fbrPostHasteAppV0_1':
return db == 'fbrPostHasteDbV0_1'
return None
The other issue is that I was not calling migrate with --database:
python manage.py migrate --database=fbrPostHasteDb
But now I am getting another error:
django.db.utils.OperationalError: FATAL: database "fbrPostHasteDbV0_1" does not exist
Continuing to figure out what else I messed up...
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