sqlalchemy 问题

• InvalidRequestError: Table is already defined for this MetaData instance. Specify 'extend_existing=True' to redefine options and columns on an existing Table object.
  • https://stackoverflow.com/questions/37908767/table-roles-users-is-already-defined-for-this-metadata-instance
  • https://stackoverflow.com/questions/15336778/using-same-name-of-tables-with-different-binds-in-flask
• sqlalchemy v0.7.8 一对多关系的backref出错
  • https://www.douban.com/group/topic/45882049/