数据库是应用开发的重要组成部分，而 ORM（对象关系映射）技术能够帮助我们用面向对象的思维操作数据库。
本篇文章将以 Python 中最流行的 ORM 框架 SQLAlchemy 为例，详细讲解如何搭建模型并实现增删改查操作。

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一、安装依赖

bash

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pip install sqlalchemy

若需要连接 MySQL 等数据库，还需安装对应驱动，例如：

bash

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pip install pymysql

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二、创建数据库连接与模型定义

python

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from sqlalchemy import create_engine, Column, Integer, String from sqlalchemy.ext.declarative import declarative_base from sqlalchemy.orm import sessionmaker # 创建数据库连接（以 SQLite 为例） engine = create_engine('sqlite:///test.db', echo=True) Base = declarative_base() class User(Base): __tablename__ = 'users' id = Column(Integer, primary_key=True) name = Column(String(50)) age = Column(Integer) def __repr__(self): return f"<User(name='{self.name}', age={self.age})>" Base.metadata.create_all(engine) Session = sessionmaker(bind=engine) session = Session()

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三、增删改查操作示例

1. 添加数据

python

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user1 = User(name='花花', age=28) session.add(user1) session.commit() print("添加成功")

2. 查询数据

python

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users = session.query(User).filter(User.age > 20).all() for user in users: print(user)

3. 更新数据

python

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user = session.query(User).filter_by(name='花花').first() if user: user.age = 29 session.commit() print("更新成功")

4. 删除数据

python

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user = session.query(User).filter_by(name='花花').first() if user: session.delete(user) session.commit() print("删除成功")

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四、总结

操作	说明
session.add()	新增对象到数据库
session.query()	查询数据
session.commit()	提交事务
session.delete()	删除对象

SQLAlchemy 作为功能强大的 ORM，不仅支持多数据库，还支持复杂关系映射，推荐在项目中使用。

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