Re: Data migration using RunPython

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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.

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> )

?

Thanks again in advance.

Sandeep

> On 5 Mar 2015, at 19:34, aRkadeFR <contact@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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