Flask sqlalchemy插入数据正常却不能正常读取什么原因，flasksqlalchemy,我写的demo程序fro

Flask sqlalchemy插入数据正常却不能正常读取什么原因，flasksqlalchemy,我写的demo程序fro

我写的demo程序

from flask import Flaskfrom flask.ext.sqlalchemy import SQLAlchemyfrom flask.ext.script import Manager,Shellapp = Flask(__name__)app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql://root:123456@127.0.0.1/hello'#app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///' + os.path.join(basedir,'data.sqlite')manager = Manager(app)db = SQLAlchemy(app)class User(db.Model):    __tablename__ = 'users'    id = db.Column(db.Integer, primary_key=True)    username = db.Column(db.String(64), unique=True)    def __repr__(self):        return '<User %r>' % self.usernamedef make_shell_context():    return dict(app=app,db=db,User=User)manager.add_command('shell',Shell(make_context=make_shell_context))if __name__ == '__main__':    manager.run()

可以再mysql插入数据，插入之前：
mysql> select * from users;
+------+-------------+---------+
| id | username | role_id |
+------+-------------+---------+
| NULL | yzxu | NULL |
| NULL | dayiguizhen | NULL |
| NULL | yzxu | NULL |
| NULL | yzxu | NULL |
| NULL | yzxu | NULL |
| NULL | yzxu | NULL |
| NULL | yzxu | NULL |
| NULL | yzxu | NULL |
| NULL | yzxu | NULL |
| NULL | yzxu | NULL |
| NULL | yzxu | NULL |
| NULL | yzxu | NULL |
| NULL | test | NULL |
+------+-------------+---------+
13 rows in set (0.00 sec)

yzxu@ubuntu:~/py/github$ python sql.py shell>>> user = User(username='after')>>> db.session.add(user)>>> db.session.commit()

插入成功：
mysql> select * from users;
+------+-------------+---------+
| id | username | role_id |
+------+-------------+---------+
| NULL | yzxu | NULL |
| NULL | dayiguizhen | NULL |
| NULL | yzxu | NULL |
| NULL | yzxu | NULL |
| NULL | yzxu | NULL |
| NULL | yzxu | NULL |
| NULL | yzxu | NULL |
| NULL | yzxu | NULL |
| NULL | yzxu | NULL |
| NULL | yzxu | NULL |
| NULL | yzxu | NULL |
| NULL | yzxu | NULL |
| NULL | test | NULL |
| NULL | after | NULL |
+------+-------------+---------+
14 rows in set (0.00 sec)

但是查询不到东西

>>> User.query.filter_by(username='after').all()[None]

但是把URI换成SQLite的就可以查询到

>>> db.create_all()>>> u = User(username='yzxu')>>> db.session.add(u)>>> db.session.commit()>>> User.query.all()[<User u'yzxu'>]>>> quit()

是不是把URI换成mysql还有进行一些其他的操作？

编橙之家文章，