我完全不知道下面内容是怎么回事，求大家帮忙解答一下？

Question

我在使用python flask框架时， 在查询数据库数据：oPropertyService = db.session.query(PropertyServiceManager).filter_by(id=psid).first()调试后出现提示错误：unable to get repr for <class 'app.model.propertyServiceManager.PropertyServiceManager'>

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Answer 1

python3下用flask-sqlalchemy对mysql数据库操作案例：from flask import Flaskfrom flask.ext.sqlalchemy import SQLAlchemyapp = Flask(__name__)app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql://username:password@localhost/db_name'db = SQLAlchemy(app)class User(db.Model):id = db.Column(db.Integer, primary_key=True)username = db.Column(db.String(80), unique=True)email = db.Column(db.String(120), unique=True)def __init__(self, username, email):self.username = usernameself.email = emaildef __repr__(self):return '<User %r>' % self.usernameadmin = User('admin', '[e-mail]')db.create_all() # In case user table doesn't exists already. Else remove it.db.session.add(admin)db.session.commit() # This is needed to write the changes to databaseUser.query.all()User.query.filter_by(username='admin').first()