Flask SQLAlchemy ImportError: cannot import Form

Solution

from flask_sqlalchemy import SQLAlchemy
db = SQLAlchemy()
def init_app(app):
    db.init_app(app)

from database import db

class AddEnqueteForm(db.Model):
    id = db.Column(db.Integer, primary_key=True)

    stelling1 = db.Column(db.String(4), nullable=False)
    stelling2 = db.Column(db.String(4), nullable=False)

[...]
from database import db
from models import *
[...]
app = Flask(__name__) 
database.init_app(app)

from main import *
with app.app_context():
     db.create_all()