Flask炼金术关联选项卡

Question

我用Flask和Flask SQLAlchemy为ORM制作了一个学费支付应用程序。在

我有一个User表，我用这个表登录学校帐户和家长帐户。{student}没有学生登录名，而数据存储在cd2表中。在

我想问的是，如何将Student表与SCOOL_ID和{}建立关系。。？而父帐户和学校帐户在同一个表中，即User表。在

一个学生有一个家长，一个学生有一所学校。在

我必须把学校和家长的桌子分开吗。。？在

到目前为止，我已经用这种烧瓶炼金术做过了，但我不确定这是否好。在

class User(db.Model, UserMixin):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(200))
    email = db.Column(db.String(120), index=True, unique=True)
    password = db.Column(db.String(255))
    active = db.Column(db.Boolean())
    created_at = db.Column(db.DateTime, default=datetime.utcnow())
    updated_at = db.Column(db.DateTime, default=datetime.utcnow())


association_roles = db.Table('association_roles',
    db.Column('parent_id', db.Integer, db.ForeignKey('user.id')),
    db.Column('school_id', db.Integer, db.ForeignKey('user.id'))
)

class Student(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    student_registration_number = db.Column(db.String(120), index=True, unique=True)
    name = db.Column(db.String(100))
    major = db.Column(db.String(50))
    created_at = db.Column(db.DateTime, default=datetime.utcnow())
    updated_at = db.Column(db.DateTime, default=datetime.utcnow())

    association_roles = db.relationship(
        'Student', secondary=association_roles,
        primaryjoin=(association_roles.c.parent_id == id),
        secondaryjoin=(association_roles.c.school_id == id),
        backref=db.backref('student', lazy='dynamic'), lazy='dynamic')

那么，怎么做呢。。？，任何帮助都将不胜感激。在

Answer 1

我已经知道我的问题的概念，我必须创建一个表学校和父表，并从表用户继承，下面是代码片段：

class User(db.Model, UserMixin):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(200))
    roles = db.relationship('Role', secondary=roles_users,
                            default='parent',
                            backref=db.backref('users', lazy='dynamic'))

    __mapper_args__ = {
        'polymorphic_identity': 'user',
        'with_polymorphic': '*'
    }

class Parent(User):
    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'))
    school_id = db.Column(db.Integer, db.ForeignKey('school.id'))

    __mapper_args__ = {
        'polymorphic_identity': 'parent',
        'with_polymorphic': '*'
    }


class School(User):
    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'))

    __mapper_args__ = {
        'polymorphic_identity': 'school',
        'with_polymorphic': '*'
    }


class Student(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(100))
    school_id = db.Column(db.Integer, db.ForeignKey('school.id'))
    parent_id = db.Column(db.Integer, db.ForeignKey('parent.id'))
    parent = db.relationship('Parent', backref=db.backref('Student', lazy='dynamic'))