Model.save_base() depends on Model._default_manager
|Reported by:||Daniel Pope <dan@…>||Owned by:||mtredinnick|
|Component:||Database layer (models, ORM)||Version:||1.0|
|Has patch:||no||Needs documentation:||no|
|Needs tests:||no||Patch needs improvement:||no|
In qs-rf, Model.save_base was refactored to check whether to perform an SQL UPDATE versus INSERT using the Model's default manager rather than raw SQL. This means that the ORM now breaks if the default manager does filtering. Any model instance that is not returned by default cannot be successfully updated. The ORM does not find the copy already saved, and tries to insert instead, causing an IntegrityError.
My manager looks like this:
class PropertyManager(models.Manager): def get_query_set(self): """By default, exclude properties not even committed""" return super(PropertyManager, self).get_query_set().exclude(status='--') def uncommitted(self): """Retrieve those properties that are not queried by default""" return super(PropertyManager, self).get_query_set().filter(status='--')
The intention was for the default manager to only return committed properties. Nowhere on the site should uncommitted properties appear: these uncommitted properties exist only while being constructed using a wizard (but need to be in the database, not just the session, so models.ImageField works).
According to the documentation for default managers (http://docs.djangoproject.com/en/dev/topics/db/managers/), you must "be careful in your choice of default manager", but this does not state that a default manager must return all rows or risk breakage.
The expectation is that saving should work regardless of the default manager.
Change History (5)
comment:1 Changed 6 years ago by Daniel Pope <dan@…>
- Needs documentation unset
- Needs tests unset
- Patch needs improvement unset
comment:3 Changed 6 years ago by mtredinnick
- Owner changed from nobody to mtredinnick
- Status changed from new to assigned
comment:4 Changed 6 years ago by mtredinnick
- Resolution set to fixed
- Status changed from assigned to closed