Python 使用SQLAlchemy克隆测试数据库

我有一个现有的数据库。该数据库通过Django应用程序进行管理。 通过Sqlalchemy模型使用相同数据库的烧瓶内应用程序使用automap_库填充：

现在我正在尝试设置测试数据库，该数据库将使用相同的基本对象创建：

因此，Sqlalchemy创建表和索引：

2014-12-17 16:23:18,499 INFO sqlalchemy.engine.base.Engine CREATE UNIQUE INDEX core_city_name_key ON core_city (name)
2014-12-17 16:23:18,499 INFO sqlalchemy.engine.base.Engine {}
2014-12-17 16:23:18,501 INFO sqlalchemy.engine.base.Engine COMMIT
2014-12-17 16:23:18,502 INFO sqlalchemy.engine.base.Engine CREATE UNIQUE INDEX core_city_name_key ON core_city (name)
2014-12-17 16:23:18,502 INFO sqlalchemy.engine.base.Engine {}
2014-12-17 16:23:18,503 INFO sqlalchemy.engine.base.Engine ROLLBACK

正如您所看到的，索引创建执行了两次并影响了错误：

ProgrammingError: (ProgrammingError) relation "core_city_name_key" already exists

我做错了什么

2014-12-17 16:23:18,499 INFO sqlalchemy.engine.base.Engine CREATE UNIQUE INDEX core_city_name_key ON core_city (name)
2014-12-17 16:23:18,499 INFO sqlalchemy.engine.base.Engine {}
2014-12-17 16:23:18,501 INFO sqlalchemy.engine.base.Engine COMMIT
2014-12-17 16:23:18,502 INFO sqlalchemy.engine.base.Engine CREATE UNIQUE INDEX core_city_name_key ON core_city (name)
2014-12-17 16:23:18,502 INFO sqlalchemy.engine.base.Engine {}
2014-12-17 16:23:18,503 INFO sqlalchemy.engine.base.Engine ROLLBACK

ProgrammingError: (ProgrammingError) relation "core_city_name_key" already exists