#28000: Migration forces "DROP DEFAULT" SQL
-------------------------------------+-------------------------------------
Reporter: Matteo Pietro Russo | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 1.9
Severity: Normal | Resolution:
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Changes (by Matteo Pietro Russo):
* status: closed => new
* resolution: invalid =>
Comment:
About default value, I read it in Django documentation:
>> "The default value is used when new model instances are created and a
value isn’t provided for the field."
It's right if I use Django ORM, but I expect my field has rule I set in my
model.
You said that "Django uses database defaults to set values on existing
rows in a table", but if I migrate my table adding default value,
migration doesn't change anything: It doesn't set default value on
existing rows, it' doesn't change field (it is nullable yet and i haven't
default).
{{{
from django.db import models
class PersonModel(models.Model):
nickname = models.CharField(max_length=100, null=True)
}}}
If I change it:
{{{
nickname = models.CharField(default="noname", max_length=100,
null=False)
}}}
makemigrations builds a migration with this operation:
{{{
migrations.AlterField(
model_name='core_personmodel',
name='nickname',
field=models.CharField(default="noname", max_length=100,
null=False),
),
}}}
If I execute migration:
{{{
Running migrations:
Rendering model states... DONE
Applying core.0004_migration... OK
}}}
but It's doesn't do anything.
--
Ticket URL: <https://code.djangoproject.com/ticket/28000#comment:3>
Django <https://code.djangoproject.com/>
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