在 sqlalchemy 中设置一对多关系，但不断收到 AmbiguousForeignKeysError

Question

I'm trying to set up a one-to-many relation between two tables (User and BlogPost, respectively). I tried copying what the course(?) solution for this and still get foreign-key errors. What do I have wrong? Or, is this actually an issue with sqlalchemy (v. 1.3.19)?

I've even tried upgrading to the current version (1.4.31) with no success. I was getting run-time errors (flask page error reports) usually around the posts = BlogPost.query.all() line in home() . Now that I've upgraded the package, I'm getting a build-time error ( AttributeError: can't set attribute ) stemming from the db.create_all() line.

I've also tried deleting the db, again with no success.

Please leave a comment if this was answered somewhere else or if more info is needed.

Here's a snippet from Main.py:

db = SQLAlchemy(app)

class User(db.Model, UserMixin):
    __tablename__ = "users"
    id = db.Column(db.Integer, primary_key=True)
    email = db.Column(db.String(250), nullable=False)
    password = db.Column(db.String(250), nullable=False)
    name = db.Column(db.String(100), nullable=False)

    posts = relationship("BlogPost", back_populates="author")


class BlogPost(db.Model):
    __tablename__ = "blog_posts"
    id = db.Column(db.Integer, primary_key=True)
    author_id = db.Column(db.Integer, db.ForeignKey("users.id"))
    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)
    user_id = db.Column(db.Integer, db.ForeignKey("users.id"))

    author = relationship("User", back_populates="posts")

db.create_all()

@app.route('/')
def home():
    posts = BlogPost.query.all()
    user = current_user
    return render_template("index.html", all_posts=posts, user=user)

Answer 1

I still don't know what's wrong, but the following code works in a newer project. Like I said in one of the comments: I suspect that there's an issue with my current PyCharm project.

db = SQLAlchemy(app)

class User(UserMixin, db.Model):
    __tablename__ = "users"
    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")


class BlogPost(db.Model):
    __tablename__ = "blog_posts"
    id = db.Column(db.Integer, primary_key=True)
    author_id = db.Column(db.Integer, db.ForeignKey("users.id"))
    author = relationship("User", back_populates="posts")
    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)

db.create_all()

@app.route('/')
def home():
    posts = BlogPost.query.all()
    return render_template("index.html", all_posts=posts)