创建个人博客网站记录-2.3 建立模型以及对应的CRUD操作

2.3、 建立模型以及对应的CRUD操作

在本节中，创建了USER用户类和BLOG博文类两个对象类，并实现了其基本的增删改查的操作。

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# flaskr/models.py
from flask import g
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy import Column,Integer,String,TIMESTAMP,ForeignKey,Text
from werkzeug.security import check_password_hash,generate_password_hash

from sqlalchemy.exc import IntegrityError

Base:SQLAlchemy = g.db

# 在此文件中创建对应的模型

# 创建用户类
class User(Base.Model):
    __tablename__ = "user"
    id = Column(Integer,primary_key=True,autoincrement=True)
    username = Column(String(20),nullable=True,unique=True)
    password_hash = Column(String(255),nullable= True)
    
    # 生成hash密码
    @staticmethod
    def hash_password(password):
        return generate_password_hash(password)
    # 验证密码
    def verify_password(self,password):
        return check_password_hash(self.password_hash,password)
    
    # 创建用户
    @classmethod
    def create(cls,username,password):
        if cls.read_by_username(username) is None:
            user = cls(username = username,password_hash = cls.hash_password(password))
            Base.session.add(user)
            Base.session.commit()
            return user
        raise IntegrityError(None,None,None)
    # 根据用户的id来读取用户
    @classmethod
    def read_by_id(cls,user_id):
        return cls.query.filter_by(id = user_id).first()
    
    #根据用户名来读取用户
    @classmethod
    def read_by_username(cls,user_name):
        return cls.query.filter_by(username = user_name).first()
    
    # 删除用户
    @classmethod
    def delete_user(cls,user_id):
        user:User = cls.read_by_id(id=user_id)
        if user:
            Base.session.delete(user)
            Base.session.commit()
            return True
        return False
    # 更新密码
    def update_password(self,new_pwd):
        self.password_hash = self.hash_password(new_pwd)
        try:
            Base.session.merge(self)
            Base.session.commit()
        except LookupError:
            return False
        return True
    
    
# 创建博文类
class Blog(Base.Model):
    __tablename__ = 'blog'
    id = Column(Integer,primary_key=True,autoincrement=True)
    author_id = Column(Integer,ForeignKey("user.id"),nullable=True)
    created = Column(TIMESTAMP,nullable=True,default=Base.func.now())
    title = Column(String(50),nullable=True)
    body = Column(Text,nullable=True)
    
    # 根据用户的id来获取post
    @classmethod
    def read_by_authorId(cls,author_id):
        return cls.query.filter_by(id=author_id).first()
    
    # 根据博文id来获取对应的内容
    @classmethod
    def read_by_blogId(cls,blog_id):
        return cls.query.filter_by(id=blog_id).first()
    
    # 创建博文
    @classmethod
    def create(cls,author_id,title,body):
        blog = cls(author_id=author_id,title=title,body=body)
        try:
            Base.session.add(blog)
            Base.session.commit()
        except IntegrityError:
            return None
        return blog
    
    # 更新博文内容
    def update(self,new_title,new_body):
        self.title = new_title
        self.body = new_body
        try:
            Base.session.merge(self)
            Base.session.commit()
        except LookupError:
            return False
        return True
    
    # 根据Id来删除博文
    @classmethod
    def delete_blog(cls,id):
        blog:Blog = cls.read_by_blogId(id)
        if blog:
            Base.session.delete(blog)
            Base.session.commit()
            return True
        return False
    
    
# 读取数据库中的所有博文
def read_all_blog():
    return list(Base.session.query(Blog,User).join(Blog,User.id == Blog.author_id).all())

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