Django : db_index and makemigrations

Question

I want to add to existing fields some db_index in my models. I just added db_index=Trueto the model.

I was thinking I would need to run python manage.py migrateto apply them on the database. My issue is that no change is detected thus no migration is created. Is it a normal behavior ?

Or is there a specific behavior I'm not aware of?

Thank you.

Django 1.7 right now, planning to make a migration to Django 1.9 soon. — Alex Grs, Dec 03 '15 at 18:17

score 1 · Answer 1 · edited May 23 '17 at 10:29

If you know enough of SQL, you can still create the migration by hand using RunSQL.

For example: (with PostgreSQL syntax)

class Migration(migrations.Migration):

    dependencies = [
        ('your_app', '0001_initial'), # or last mig
    ]

    operations = [
        migrations.RunSQL("CREATE INDEX my_table_my_column_ind ON my_table (my_colum)"),
    ]

Related: Creating Partial Indexes with Django 1.7

score 0 · Answer 2 · answered Dec 03 '15 at 18:04

0

you can use index_together

class YourModel(models.Model):
    # ...

    class Meta:
        index_together = ["field_that_needs_index"]

then makemigration should work

answered Dec 03 '15 at 18:04

doniyor

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Is there really no way to only add db_index? I have 2 / 3 indexes to create on my models ? – Alex Grs Dec 03 '15 at 18:20
set the db_index in the fields also, but you need migration for it, so add these fields in index_together also. – doniyor Dec 03 '15 at 18:28
Ok. how can I check then that my indexes are created ? Creating thos index_together will not cause issues with writes / or database size ? – Alex Grs Dec 03 '15 at 18:44
@AlexGrs nope, no issues. `SHOW INDEX FROM [tablename]` will show you the indexes from your tables – doniyor Dec 04 '15 at 04:02

Django : db_index and makemigrations

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