On 03/05/2015 10:01 AM, Murthy Sandeep wrote:
Thanks,
Two further questions if you don’t mind:
1. I am in the Python interpreter and am working with
one of my db models called SmallGroup.
When I do SmallGroup.objects.all() I get the following message:
File "<console>", line 1, in <module>
File "/Library/Python/2.7/site-packages/django/db/models/query.py", line
119, in __repr__
return repr(data)
File "/Library/Python/2.7/site-packages/django/db/models/base.py", line 458,
in __repr__
u = six.text_type(self)
TypeError: coercing to Unicode: need string or buffer, SmallGroup found
Does this have something to do with the method `__str__` which I added
to this model in my `models.py`? I don’t think I did a ‘python manage.py
migrate’ after
the change though.
There's two problems yeah, you didn't run your migrations, and maybe
you have unicode encoding problem.
Please, check the documentation on migration[1] and unicode[2].
2. If I want to modify or delete entries in the db table SmallGroup are there
methods corresponding to `bulk_create` for doing this? Something like
Country.objects.using(db_alias).bulk_update( <list> )
Country.objects.using(db_alias).bulk_delete( <list> )
?
You have all you need in the documentation [3].
You have the .update and .delete methods on a queryset.
Thanks again in advance.
Sandeep
[1] migrations: https://docs.djangoproject.com/en/1.7/topics/migrations/
[2] unicode with python 2: https://docs.python.org/2/howto/unicode.html
[3] https://docs.djangoproject.com/en/1.7/topics/db/queries/
On 5 Mar 2015, at 19:34, aRkadeFR <cont...@arkade.info> wrote:
Hello,
In Django, you can instanciate objects from your model without
persist it to the database. The way you do it is Country(name=..., ...).
In order to create multiple objects at once, you can
call the bulk_create method on the manager with a list
of object to persist.
The using(db_alias) is instanciating the manager.
I won't explain further cause my knowledge of this area
is reduced.
Have a good one
On 03/05/2015 01:20 AM, Murthy Sandeep wrote:
I am working on a data migration for my Django app to populate
the main table in the db with data that will form the mainstay of
the app - this is persistent/permanent data that may added to but
never deleted.
My reference is the Django 1.7 documentation and in particular an
example on page
https://docs.djangoproject.com/en/1.7/ref/migration-operations/#django.db.migrations.operations.RunPython
with a custom method called forward_funcs:
def forwards_func(apps, schema_editor):
# We get the model from the versioned app registry;
# if we directly import it, it'll be the wrong version
Country = apps.get_model("myapp", "Country")
db_alias = schema_editor.connection.alias
Country.objects.using(db_alias).bulk_create([
Country(name="USA", code="us"),
Country(name="France", code="fr"),])
I was wondering if someone could please explain what is happening
here and how this method works - is the argument to bulk_create a
list of namedtuple objects called Country or are these Country model
objects?
Also could someone please explain what db_alias is?
Sandeep
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