I have the same problem, looks like it's a bug: https://code.djangoproject.com/ticket/18896
On Friday, 31 August 2012 18:55:39 UTC-4, Matt Long wrote: > > Bump? > > Almost exactly 4 years later, I've ran into this exact same issue in > Django 1.4. Attempting to use get_or_create through a ManyToMany field > results in an integrity error if the object already exists but is not yet > associated with the parent object. To use the OP's example, if a Tag with > name "foo" exists but is not yet associated with a given Thing instance, > using .tags.get_or_create(name='foo') will indeed raise an IntegrityError: > > foo_tag = Tag(name='foo') > foo_tag.save() > > a_thing = Thing(name='a') > a_thing.save() > a_thing.tags.get_or_create(name='foo') > > Traceback (most recent call last): > File "<input>", line 1, in <module> > File > "/usr/local/lib/python2.7/dist-packages/django/db/models/fields/related.py", > line 616, in get_or_create > super(ManyRelatedManager, self.db_manager(db)).get_or_create(**kwargs) > File > "/usr/local/lib/python2.7/dist-packages/django/db/models/manager.py", line > 134, in get_or_create > return self.get_query_set().get_or_create(**kwargs) > File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", > line 449, in get_or_create > obj.save(force_insert=True, using=self.db) > File "/usr/local/lib/python2.7/dist-packages/django/db/models/base.py", > line 463, in save > self.save_base(using=using, force_insert=force_insert, > force_update=force_update) > File "/usr/local/lib/python2.7/dist-packages/django/db/models/base.py", > line 551, in save_base > result = manager._insert([self], fields=fields, return_id=update_pk, > using=using, raw=raw) > File > "/usr/local/lib/python2.7/dist-packages/django/db/models/manager.py", line > 203, in _insert > return insert_query(self.model, objs, fields, **kwargs) > File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", > line 1576, in insert_query > return query.get_compiler(using=using).execute_sql(return_id) > File > "/usr/local/lib/python2.7/dist-packages/django/db/models/sql/compiler.py", > line 910, in execute_sql > cursor.execute(sql, params) > File > "/usr/local/lib/python2.7/dist-packages/django/db/backends/util.py", line > 40, in execute > return self.cursor.execute(sql, params) > File > "/usr/local/lib/python2.7/dist-packages/django/db/backends/sqlite3/base.py", > line 337, in execute > return Database.Cursor.execute(self, query, params) > IntegrityError: column name is not unique > > I've traced the problem to being that the ManyRelatedManager includes its > core_filters in its get_query_set method. This results in the "get" portion > of get_or_create to only return a hit if the Tag exists and is already > associated to the calling Thing instance. Given the nature of a > many-to-many relationship, it should not be a requirement that a Tag > already be linked to the calling Thing for get_or_create to find it; it > should be enough that the Tag simply exists. All that should happen in that > scenario is that the (existing) Tag's relationship with the calling Thing > be created/saved. > > On Monday, September 1, 2008 8:04:00 PM UTC-7, Cap wrote: >> >> I'm having problems using get_or_create with a ManyToManyField and I'm >> not sure whether the problem is me or Django. >> >> I have two models: >> >> class Tag(models.Model): >> name = models.CharField(max_length=256, unique=True) >> >> class Thing(models.Model): >> name = models.CharField(max_length=256) >> tags = models.ManyToManyField(Tag) >> >> When I try to add a tag that already exists, as: >> >> a = Thing(name='a') >> a.save() >> a.tags.get_or_create(name='foo') >> >> I get sqlite3.IntegrityError: column name is not unique. >> >> But when I do it like so: >> >> a = Thing(name='a') >> a.save() >> foo, created = Tag.objects.get_or_create(name='foo') >> a.tags.add(foo) >> >> I have no problems. >> >> I noticed that http://code.djangoproject.com/ticket/3121 seemed to >> address something like this, so I pulled the latest Django (8834), but >> the problems remains. >> >> Am I doing it wrong? >> > -- You received this message because you are subscribed to the Google Groups "Django users" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-users+unsubscr...@googlegroups.com. To post to this group, send email to django-users@googlegroups.com. Visit this group at http://groups.google.com/group/django-users?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
