orm ['model']。objects.create（attr = some_value）はIntegrityErrorを発生させます

Question

私のモデルのバックログとエンティティとの間には一対一の関係があります。各バックログにはエンティティがあります。 バックログに1つのエンティティが存在しない場合（エンティティがdbに存在しない場合）、そのエンティティを失ったバックログにリンクします。

  new_entity = orm['entities.entity'].objects.create(long_name=entity_name) 
      if entity_short_name is not None and entity_short_name != '': 
       new_entity.name = entity_short_name 
      if entity_url is not None: 
       new_entity.primary_url = entity_url 
      new_entity.save() 
      backlog.entity = new_entity 
      backlog.save() 

各エンティティオブジェクトには、GUIDという一意のIDがあります。 これは、私は上記のコードで取得エラー：この整合性エラーを引き起こしている可能性が何

guid = models.CharField('A globally unique identifier', default = lambda: str(uuid.uuid4()), unique = True, db_index = True) 

：

django.db.utils.IntegrityError: duplicate key value violates unique constraint "entities_entity_guid_uniq" 
DETAIL: Key (guid)=(2f49223d-8732-4582-b8a1-7015f515134a) already exists. 

エンティティモデル一つだけのユニークな鍵を持っていますか？このGUIDを持つエンティティがDBに存在する場合にチェックすることなし

を返しません。** ORMはデシベル

File "./manage.py", line 10, in <module> 
    execute_from_command_line(sys.argv) 
    File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 399, in execute_from_command_line 
    utility.execute() 
    File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 392, in execute 
    self.fetch_command(subcommand).run_from_argv(self.argv) 
    File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 242, in run_from_argv 
    self.execute(*args, **options.__dict__) 
    File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 285, in execute 
    output = self.handle(*args, **options) 
    File "/usr/local/lib/python2.7/dist-packages/south/management/commands/migrate.py", line 111, in handle 
    ignore_ghosts = ignore_ghosts, 
    File "/usr/local/lib/python2.7/dist-packages/south/migration/__init__.py", line 220, in migrate_app 
    success = migrator.migrate_many(target, workplan, database) 
    File "/usr/local/lib/python2.7/dist-packages/south/migration/migrators.py", line 254, in migrate_many 
    result = migrator.__class__.migrate_many(migrator, target, migrations, database) 
    File "/usr/local/lib/python2.7/dist-packages/south/migration/migrators.py", line 329, in migrate_many 
    result = self.migrate(migration, database) 
    File "/usr/local/lib/python2.7/dist-packages/south/migration/migrators.py", line 133, in migrate 
    result = self.run(migration, database) 
    File "/usr/local/lib/python2.7/dist-packages/south/migration/migrators.py", line 114, in run 
    return self.run_migration(migration, database) 
    File "/usr/local/lib/python2.7/dist-packages/south/migration/migrators.py", line 84, in run_migration 
    migration_function() 
    File "/usr/local/lib/python2.7/dist-packages/south/migration/migrators.py", line 60, in <lambda> 
    return (lambda: direction(orm)) 
    File "/usr/local/PATH/0123__.py", line 69, in forwards 
    new_entity = orm['entities.entity'].objects.create(long_name=entity_name) 
    File "/usr/local/lib/python2.7/dist-packages/django/db/models/manager.py", line 157, in create 
    return self.get_queryset().create(**kwargs) 
    File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 322, in create 
    obj.save(force_insert=True, using=self.db) 
    File "/usr/local/lib/python2.7/dist-packages/django/db/models/base.py", line 545, in save 
    force_update=force_update, update_fields=update_fields) 
    File "/usr/local/lib/python2.7/dist-packages/django/db/models/base.py", line 573, in save_base 
    updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields) 
    File "/usr/local/lib/python2.7/dist-packages/django/db/models/base.py", line 654, in _save_table 
    result = self._do_insert(cls._base_manager, using, fields, update_pk, raw) 
    File "/usr/local/lib/python2.7/dist-packages/django/db/models/base.py", line 687, in _do_insert 
    using=using, raw=raw) 
    File "/usr/local/lib/python2.7/dist-packages/django/db/models/manager.py", line 232, in _insert 
    return insert_query(self.model, objs, fields, **kwargs) 
    File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 1514, 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 903, in execute_sql 
    cursor.execute(sql, params) 
    File "/usr/local/lib/python2.7/dist-packages/django/db/backends/util.py", line 69, in execute 
    return super(CursorDebugWrapper, self).execute(sql, params) 
    File "/usr/local/lib/python2.7/dist-packages/django/db/backends/util.py", line 53, in execute 
    return self.cursor.execute(sql, params) 
    File "/usr/local/lib/python2.7/dist-packages/django/db/utils.py", line 99, in __exit__ 
    six.reraise(dj_exc_type, dj_exc_value, traceback) 
    File "/usr/local/lib/python2.7/dist-packages/django/db/backends/util.py", line 53, in execute 
    return self.cursor.execute(sql, params) 
django.db.utils.IntegrityError: duplicate key value violates unique constraint "entities_entity_guid_uniq" 
DETAIL: Key (guid)=(2f49223d-8732-4582-b8a1-7015f515134a) already exists. 

Answer 1

からオブジェクトを取得するための標準的なDjangoのORMは、あなたの​​フィールドでの問題は、あなたが設定されていることですだけではなく、修正するために、新しいオブジェクトが作成されるたびに呼び出されますどの呼び出し可能な設定のデフォルト値としてuuid.uuid4()呼び出し可能の結果：

def get_unique_id(): 
    return str(uuid.uuid4()) 

guid = models.CharField('A globally unique identifier', default=get_unique_id, unique=True, db_index=True) 

がmakemigrationsとを実行することを忘れないでください。この変更後10。