从手写持久层迁移到 ORM

从手写持久层迁移到ORM：提升开发效率的智慧选择

python
# 手写持久层代码
import sqlite3
class UserDAO:
    def __init__(self, db_path):
        self.connection = sqlite3.connect(db_path)
        self.cursor = self.connection.cursor()
    def find_all_users(self):
        query = "SELECT * FROM users"
        self.cursor.execute(query)
        return self.cursor.fetchall()
    def add_user(self, username, email):
        query = f"INSERT INTO users (username, email) VALUES ('{username}', '{email}')"
        self.cursor.execute(query)
        self.connection.commit()
# 使用手写持久层
user_dao = UserDAO("mydatabase.db")
users = user_dao.find_all_users()
print("All Users:", users)
user_dao.add_user("JohnDoe", "john@example.com")

python
# 使用ORM框架
from sqlalchemy import create_engine, Column, String, Integer
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
Base = declarative_base()
class User(Base):
    __tablename__ = 'users'
    id = Column(Integer, primary_key=True)
    username = Column(String)
    email = Column(String)
# 创建数据库引擎和会话
engine = create_engine('sqlite:///mydatabase.db')
Base.metadata.create_all(engine)
Session = sessionmaker(bind=engine)
session = Session()
# 使用ORM进行数据库操作
all_users = session.query(User).all()
print("All Users:", all_users)
new_user = User(username="JaneDoe", email="jane@example.com")
session.add(new_user)
session.commit()