models.py

from flask import Flask
from flask_login import UserMixin
from sqlalchemy.orm import relationship
from flask_sqlalchemy import SQLAlchemy


app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///posts.db'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
app.config['SECRET_KEY'] = '8BYkEfBA6O6donzWlSihBXox7C0sKR6b'
db = SQLAlchemy(app)



class User(UserMixin, db.Model):
    id = db.Column(db.Integer, primary_key=True)
    email = db.Column(db.String(100), unique=True)
    password = db.Column(db.String(100))
    name = db.Column(db.String(100))

    posts = relationship("BlogPost", back_populates="author", lazy='subquery')
    comments = relationship("Comment", back_populates="author", lazy='subquery')


class BlogPost(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    author_id = db.Column(db.Integer, db.ForeignKey("user.id"))
    author = relationship("User", back_populates="posts", lazy='subquery')
    title = db.Column(db.String(250), unique=True, nullable=False)
    subtitle = db.Column(db.String(250), nullable=False)
    date = db.Column(db.String(250), nullable=False)
    body = db.Column(db.Text, nullable=False)
    img_url = db.Column(db.String(250), nullable=False)
    comments = relationship("Comment", back_populates="blog", lazy='subquery')


class Comment(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    author_id = db.Column(db.Integer, db.ForeignKey("user.id"))
    author = relationship("User", back_populates="comments", lazy='subquery')
    text = db.Column(db.String(250), nullable=False)
    blog = relationship("BlogPost", back_populates="comments", lazy='subquery')
    post_id = db.Column(db.Integer, db.ForeignKey(BlogPost.id))


with app.app_context():
    db.create_all()