如何从orm中获取数据库值，如何在odoo 8中从string中获取字段名

from sqlalchemy import create_engine, Column, Integer, String
from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.declarative import declarative_base

# 建立数据库连接
engine = create_engine('mysql://username:password@host:port/database')

# 创建会话工厂
Session = sessionmaker(bind=engine)

# 创建基础模型类
Base = declarative_base()

# 定义数据模型类
class User(Base):
    __tablename__ = 'users'
    id = Column(Integer, primary_key=True)
    name = Column(String(50))
    email = Column(String(100))

# 创建会话对象
session = Session()

# 查询数据并获取字段值
user = session.query(User).filter_by(name='John').first()
name = user.name
email = user.email

# 打印字段值
print(f'Name: {name}')
print(f'Email: {email}')

from openerp import models

# 获取模型类
class MyModel(models.Model):
    _name = 'my.model'
    _description = 'My Model'

# 定义字符串字段名
field_name = 'my_field'

# 获取字段对象
field = MyModel._fields.get(field_name)

# 判断字段是否存在
if field:
    print(f'Field "{field_name}" exists in MyModel')
else:
    print(f'Field "{field_name}" does not exist in MyModel')