models.py

from flask_sqlalchemy import SQLAlchemy

db = SQLAlchemy()


class User(db.Model):
    __tablename__ = 'users'
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String, unique=True, nullable=False)
    password = db.Column(db.String, nullable=False)


class Book(db.Model):
    __tablename__ = 'books'
    id = db.Column(db.Integer, primary_key=True)
    isbn = db.Column(db.String, nullable=False)
    title = db.Column(db.String, nullable=False)
    author = db.Column(db.String, nullable=False)
    pub = db.Column(db.String, nullable=False)
    reviews = db.relationship('Review', backref='book', lazy=True)

    def add_review(self, user_id, comment):
        review = Review(book_id=self.id, user_id=user_id, comment=comment)
        db.session.add(review)
        db.session.commit()


class Review(db.Model):
    __tablename__ = 'reviews'
    id = db.Column(db.Integer, primary_key=True)
    book_id = db.Column(db.Integer, db.ForeignKey('books.id'), nullable=False)
    user_name = db.Column(db.String, db.ForeignKey('users.name'), nullable=False)
    rating = db.Column(db.Integer, nullable=False)
    comment = db.Column(db.Text, nullable=False)