default value in model not set in db schema

Using Django Using the ORM
1

I’ve a problem with creating tablets in mariadb. For now, in my project, I create tables from outside django thru SQL statements in python script and some with models that make mess and problems with migrations (table exists errors etc.).

I decided to use only models, but if I set


price = models.IntegerField(null=True, default=0)

default value in martiadb is NULL not 0

I found some old threads in internet suggest that default, not set db schema default value, but maybe something changed?

I need this because this project isn’t pure django and some other parts use default values sets by db durning input data.

1 Like
2

The default for a field is not set as an attribute in the database.

Django allows for a callable to be used as the default, so that’s not a setting that can be managed by the database, it needs to be done within Django itself.

The default value is handled by the __init__ method of the model class when the instance is created.

3

Well it’s little messy because other attributes make settings in db. So in my situation it’s better to do the database outside of django and in models

 class Meta:
    managed = False

This should eliminate “table exists errors” during migration.
Is there any other solution to go 100% to django models/ORM with setting default in db?

4

Model attributes, yes. Field attributes, not so much. The majority of field options such as choices, auto_now, upload_to, etc are managed within Django. (The exceptions being the DB-specific attributes such as db_column or primary_key among a couple others.)

You can create a custom migration to issue the necessary DDL commands as SQL on the database. See Data Migrations and Special Operations.