为什么使用sqlite在sqlalchemy中未绑定会话方法?

问题描述

代码复制错误:

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

Base = declarative_base()

class Message(Base):
    __tablename__ = 'messages'

    id = Column(Integer, primary_key=True)
    message = Column(Integer)


engine = create_engine('sqlite:///' + filename_of_your_choice)
session = sessionmaker(bind=engine)

newmessage = Message()
newmessage.message = "Hello"

messages = session.query(Message).all()

运行此代码产生:

Traceback (most recent call last):
  File "C:/aaron/test.py", line 20, in <module>
    session.commit()
TypeError: unbound method commit() must be called with Session instance as first argument (got nothing instead)

我 95% 肯定文件名不是问题，因为我可以从 shell 连接到它

I'm 95% positive that the filename isn't the issue as I can connect to it from the shell

有什么想法吗?

推荐答案

sessionmaker() 的返回值 是一个类.在实例上使用方法之前，您需要对其进行实例化.

The return value from sessionmaker() is a class. You need to instantiate it before using methods on the instance.

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