Flask中定义模型类的情况分别有哪些

Flask中定义模型类的情况分别有哪些，相信很多没有经验的人对此束手无策，为此本文总结了问题出现的原因和解决方法，通过这篇文章希望你能解决这个问题。

from datetime import datetimefrom werkzeug.security import generate_password_hash, check_password_hashfrom utils import constantsfrom . import dbclass BaseModel(object):    """模型基类，为每个模型补充创建时间与更新时间"""    create_time = db.Column(db.DateTime, default=datetime.now)  # 记录的创建时间    update_time = db.Column(db.DateTime, default=datetime.now, onupdate=datetime.now)  # 记录的更新时间# 用户收藏表，建立用户与其收藏新闻多对多的关系tb_user_collection = db.Table(    "info_user_collection",    db.Column("user_id", db.Integer, db.ForeignKey("info_user.id"), primary_key=True),  # 新闻编号    db.Column("news_id", db.Integer, db.ForeignKey("info_news.id"), primary_key=True),  # 分类编号    db.Column("create_time", db.DateTime, default=datetime.now)  # 收藏创建时间)tb_user_follows = db.Table(    "info_user_fans",    db.Column('follower_id', db.Integer, db.ForeignKey('info_user.id'), primary_key=True),  # 粉丝id    db.Column('followed_id', db.Integer, db.ForeignKey('info_user.id'), primary_key=True)  # 被关注人的id)class User(BaseModel, db.Model):    """用户"""    __tablename__ = "info_user"    id = db.Column(db.Integer, primary_key=True)  # 用户编号    nick_name = db.Column(db.String(32), unique=True, nullable=False)  # 用户昵称    password_hash = db.Column(db.String(128), nullable=False)  # 加密的密码    mobile = db.Column(db.String(11), unique=True, nullable=False)  # 手机号    avatar_url = db.Column(db.String(256))  # 用户头像路径    last_login = db.Column(db.DateTime, default=datetime.now)  # 最后一次登录时间    is_admin = db.Column(db.Boolean, default=False)    signature = db.Column(db.String(512))  # 用户签名    gender = db.Column(  # 订单的状态        db.Enum(            "MAN",  # 男            "WOMAN"  # 女        ),        default="MAN")    # 当前用户收藏的所有新闻    collection_news = db.relationship("News", secondary=tb_user_collection, lazy="dynamic")  # 用户收藏的新闻    # 用户所有的粉丝，添加了反向引用followed，代表用户都关注了哪些人    followers = db.relationship('User',                                secondary=tb_user_follows,                                primaryjoin=id == tb_user_follows.c.followed_id,                                secondaryjoin=id == tb_user_follows.c.follower_id,                                backref=db.backref('followed', lazy='dynamic'),                                lazy='dynamic')    # 当前用户所发布的新闻    news_list = db.relationship('News', backref='user', lazy='dynamic')    @property    def password(self):        raise AttributeError("当前属性不可读")    @password.setter    def password(self, value):        self.password_hash = generate_password_hash(value)    def check_passowrd(self, password):        return check_password_hash(self.password_hash, password)    def to_dict(self):        resp_dict = {            "id": self.id,            "nick_name": self.nick_name,            "avatar_url": constants.QINIU_DOMIN_PREFIX + self.avatar_url if self.avatar_url else "",            "mobile": self.mobile,            "gender": self.gender if self.gender else "MAN",            "signature": self.signature if self.signature else "",            "followers_count": self.followers.count(),            "news_count": self.news_list.count()        }        return resp_dict    def to_admin_dict(self):        resp_dict = {            "id": self.id,            "nick_name": self.nick_name,            "mobile": self.mobile,            "register": self.create_time.strftime("%Y-%m-%d %H:%M:%S"),            "last_login": self.last_login.strftime("%Y-%m-%d %H:%M:%S"),        }        return resp_dictclass News(BaseModel, db.Model):    """新闻"""    __tablename__ = "info_news"    id = db.Column(db.Integer, primary_key=True)  # 新闻编号    title = db.Column(db.String(256), nullable=False)  # 新闻标题    source = db.Column(db.String(64), nullable=False)  # 新闻来源    digest = db.Column(db.String(512), nullable=False)  # 新闻摘要    content = db.Column(db.Text, nullable=False)  # 新闻内容    clicks = db.Column(db.Integer, default=0)  # 浏览量    index_image_url = db.Column(db.String(256))  # 新闻列表图片路径    category_id = db.Column(db.Integer, db.ForeignKey("info_category.id"))    user_id = db.Column(db.Integer, db.ForeignKey("info_user.id"))  # 当前新闻的作者id    status = db.Column(db.Integer, default=0)  # 当前新闻状态 如果为0代表审核通过，1代表审核中，-1代表审核不通过    reason = db.Column(db.String(256))  # 未通过原因，status = -1 的时候使用    # 当前新闻的所有评论    comments = db.relationship("Comment", lazy="dynamic")    def to_review_dict(self):        resp_dict = {            "id": self.id,            "title": self.title,            "create_time": self.create_time.strftime("%Y-%m-%d %H:%M:%S"),            "status": self.status,            "reason": self.reason if self.reason else ""        }        return resp_dict    def to_basic_dict(self):        resp_dict = {            "id": self.id,            "title": self.title,            "source": self.source,            "digest": self.digest,            "create_time": self.create_time.strftime("%Y-%m-%d %H:%M:%S"),            "index_image_url": self.index_image_url,            "clicks": self.clicks,        }        return resp_dict    def to_dict(self):        resp_dict = {            "id": self.id,            "title": self.title,            "source": self.source,            "digest": self.digest,            "create_time": self.create_time.strftime("%Y-%m-%d %H:%M:%S"),            "content": self.content,            "comments_count": self.comments.count(),            "clicks": self.clicks,            "category": self.category.to_dict(),            "index_image_url": self.index_image_url,            "author": self.user.to_dict() if self.user else None        }        return resp_dictclass Comment(BaseModel, db.Model):    """评论"""    __tablename__ = "info_comment"    id = db.Column(db.Integer, primary_key=True)  # 评论编号    user_id = db.Column(db.Integer, db.ForeignKey("info_user.id"), nullable=False)  # 用户id    news_id = db.Column(db.Integer, db.ForeignKey("info_news.id"), nullable=False)  # 新闻id    content = db.Column(db.Text, nullable=False)  # 评论内容    parent_id = db.Column(db.Integer, db.ForeignKey("info_comment.id"))  # 父评论id    parent = db.relationship("Comment", remote_side=[id])  # 自关联    like_count = db.Column(db.Integer, default=0)  # 点赞条数    def to_dict(self):        resp_dict = {            "id": self.id,            "create_time": self.create_time.strftime("%Y-%m-%d %H:%M:%S"),            "content": self.content,            "parent": self.parent.to_dict() if self.parent else None,            "user": User.query.get(self.user_id).to_dict(),            "news_id": self.news_id,            "like_count": self.like_count        }        return resp_dictclass CommentLike(BaseModel, db.Model):    """评论点赞"""    __tablename__ = "info_comment_like"    comment_id = db.Column("comment_id", db.Integer, db.ForeignKey("info_comment.id"), primary_key=True)  # 评论编号    user_id = db.Column("user_id", db.Integer, db.ForeignKey("info_user.id"), primary_key=True)  # 用户编号class Category(BaseModel, db.Model):    """新闻分类"""    __tablename__ = "info_category"    id = db.Column(db.Integer, primary_key=True)  # 分类编号    name = db.Column(db.String(64), nullable=False)  # 分类名    news_list = db.relationship('News', backref='category', lazy='dynamic')    def to_dict(self):        resp_dict = {            "id": self.id,            "name": self.name        }        return resp_dict

看完上述内容，你们掌握Flask中定义模型类的情况分别有哪些的方法了吗？如果还想学到更多技能或想了解更多相关内容，欢迎关注行业资讯频道，感谢各位的阅读！