相关疑难解决方法(0)

我试图改变一个没有主键和auto_increment列的表.我知道如何添加主键列,但我想知道是否可以自动将数据插入主键列(我已经在DB中有500行并且想要给它们id,但我不想手动执行) .有什么想法吗？非常感谢.

我已经阅读了文档,但我无法在任何地方找到相关说明.我尝试删除旧密钥并添加一个新密钥,但这会让我产生错误:

op.drop_constraint('PRIMARY', 'some_table', type_='primary')
op.create_primary_key('PRIMARY', 'some_table', ['col1', 'col2'])

sqlalchemy.exc.OperationalError: (OperationalError) (1025, "Error on rename of ... (errno: 150 - Foreign key constraint is incorrectly formed)") 'ALTER TABLE some_table DROP PRIMARY KEY ' ()

我究竟做错了什么？

我有一个SQLAlchemy模型，例如-

class UserFavPlace(db.Model):
    # This model stores the feedback from the user whether he has
    # faved a place or not
    __tablename__ = u'user_fav_places'

    id = db.Column(db.Integer, primary_key = True)
    public_place_id = db.Column(db.Integer, db.ForeignKey(u'public_places.id'))
    user_id = db.Column(db.Integer, db.ForeignKey(u'users.user_id'))
    fav = db.Column(db.Boolean)
    updated_time = db.Column(db.DateTime)

    place = relationship(u'PublicPlace', backref = u'user_fav_places')
    user = relationship(u'User', backref = u'user_fav_places')

然后，我将此模型更改为以下模型-

class UserFavPlace(db.Model):
    # This model stores the feedback from the user whether he has
    # faved a place or not
    __tablename__ = u'user_fav_places' …