Flask / SqlAlchemy / Graphene -如何从数据库中查询对象并更改值？

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from graphene import ObjectType, String, Schema

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = '数据库连接字符串'
db = SQLAlchemy(app)

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(50))
    email = db.Column(db.String(50))

class UserType(ObjectType):
    id = String()
    name = String()
    email = String()

class Query(ObjectType):
    user = String(id=String(required=True))
    
    def resolve_user(root, info, id):
        user = User.query.get(id)
        return UserType(id=user.id, name=user.name, email=user.email)

class Mutation(ObjectType):
    update_user = String(id=String(required=True), name=String(), email=String())
    
    def resolve_update_user(root, info, id, name=None, email=None):
        user = User.query.get(id)
        if name:
            user.name = name
        if email:
            user.email = email
        db.session.commit()
        return 'User updated successfully'

schema = Schema(query=Query, mutation=Mutation)

if __name__ == '__main__':
    app.run()