from flask_sqlalchemy import SQLAlchemy

db = SQLAlchemy()

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(50), nullable=False)
    posts = db.relationship('Post', backref='user', lazy=True)

class Post(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    title = db.Column(db.String(100), nullable=False)
    content = db.Column(db.Text, nullable=False)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)

from flask import Flask
from flask_sqlalchemy import SQLAlchemy

# 初始化 Flask 应用
app = Flask(__name__)

# 配置数据库
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///blog.db'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False

# 初始化数据库连接
db = SQLAlchemy(app)

# 导入模型
from models import User, Post

from models import User, Post

# 创建用户
user1 = User(name='Alice')
user2 = User(name='Bob')

# 创建文章
post1 = Post(title='First post', content='This is my first post!', user=user1)
post2 = Post(title='Second post', content='This is my second post!', user=user1)
post3 = Post(title='Hello, World!', content='This is my first post on my new blog', user=user2)

# 将用户和文章添加到数据库
db.session.add(user1)
db.session.add(user2)
db.session.add(post1)
db.session.add(post2)
db.session.add(post3)
db.session.commit()

from models import User

# 查询用户的文章
user = User.query.get(1)
posts = user.posts

# 打印用户的文章标题
for post in posts:
    print(post.title)