sqlalchemy.exc.OperationalError: (sqlite3.OperationalError) no such table

I just got done setting up a Flask app and I dealt with this kind of problem.

I strongly suspect the problem here is that the instance of db that you are creating in __init__.py is unaware of the contents of models.py, including the User class. The db object in __init__.py is a totally separate object from the db you are creating in models.py. So when you run db.create_all() in __init__.py, it is checking the list of tables that it knows about and isn't finding any. I ran into this exact issue.

What I discovered is that the models (like User) are registered with the particular db object that is listed in the model's class definition (e.g. class User(db.Model):).

So basically my understanding is that the way to fix this is to run db.create_all() using the same instance of db that is being used to define the models. In other words, run db.create_all() from within models.py.

Here's my code so you can see how I have it set up:

app.py:

#!flask/bin/pythonimport osfrom flask import Flaskclass CustomFlask(Flask):    jinja_options = Flask.jinja_options.copy()    jinja_options.update(dict(        variable_start_string='%%',  # Default is '{{', I'm changing this because Vue.js uses '{{' / '}}'        variable_end_string='%%',    ))app = CustomFlask(__name__)app.config['SECRET_KEY'] = 'hard to guess string'import yamlif os.environ['SERVER_ENVIRONMENT'] == 'PRODUCTION':    config_filename = "production.yaml"elif os.environ['SERVER_ENVIRONMENT'] == 'LOCAL':    config_filename = "local.yaml"else:    config_filename = "local.yaml"base_directory = path = os.path.dirname(os.path.realpath(__file__))with open(base_directory + "/config/" + config_filename) as config_file:    config = yaml.load(config_file)db_config = config['database']SQLALCHEMY_DATABASE_URI = "mysql+mysqlconnector://{username}:{password}@{hostname}/{databasename}".format(    username=db_config['username'],    password=db_config['password'],    hostname=db_config['hostname'],    databasename=db_config['databasename'],)app.config["SQLALCHEMY_DATABASE_URI"] = SQLALCHEMY_DATABASE_URIapp.config["SQLALCHEMY_POOL_RECYCLE"] = 299from flask_sqlalchemy import SQLAlchemydb = SQLAlchemy(app)db.app = appdef clear_the_template_cache():    app.jinja_env.cache = {}app.before_request(clear_the_template_cache)from flask_login import LoginManagerlogin_manager = LoginManager()login_manager.init_app(app)@login_manager.user_loaderdef load_user(email):    from models import User    return User.query.filter_by(email=email).first()if __name__ == '__main__':    from routes import web_routes    app.register_blueprint(web_routes)    from api import api    app.register_blueprint(api)    # To get PyCharm's debugger to work, you need to have "debug=False, threaded=True"    #app.run(debug=False, threaded=True)    app.run(debug=True)

models.py:

from app import dbimport datetimefrom werkzeug.security import generate_password_hash, \     check_password_hashclass Song(db.Model):    id = db.Column(db.Integer, primary_key=True, autoincrement=True)    name = db.Column(db.String(80))    datetime_created = db.Column(db.DateTime, default=datetime.datetime.utcnow())    user_id = db.Column(db.Integer, db.ForeignKey('user.id'))    lines = db.relationship('Line', cascade="all,delete", backref=db.backref('song', lazy='joined'), lazy='dynamic')    is_deleted = db.Column(db.Boolean, default=False)class Line(db.Model):    id = db.Column(db.Integer, primary_key=True, autoincrement=True)    user_id = db.Column(db.Integer, db.ForeignKey('user.id'))    song_id = db.Column(db.Integer, db.ForeignKey('song.id'))    spans_of_time = db.relationship('SpanOfTime', cascade="all,delete", backref=db.backref('line', lazy='joined'), lazy='dynamic')class SpanOfTime(db.Model):    id = db.Column(db.Integer, primary_key=True, autoincrement=True)    user_id = db.Column(db.Integer, db.ForeignKey('user.id'))    line_id = db.Column(db.Integer, db.ForeignKey('line.id'))    starting_64th = db.Column(db.Integer)  # I'm assuming the highest-granularity desired will be a 1/64th note-length.    length = db.Column(db.Integer)  # I guess this'll be in 1/64th notes, so a 1/16th note will be '4'.    content = db.Column(db.String(80))class User(db.Model):    id = db.Column(db.Integer, primary_key=True, autoincrement=True)    email = db.Column(db.String(80), primary_key=True, unique=True)    display_name = db.Column(db.String(80), default="A Rhymecraft User")    password_hash = db.Column(db.String(200))    datetime_subscription_valid_until = db.Column(db.DateTime, default=datetime.datetime.utcnow() - datetime.timedelta(days=1))    datetime_joined = db.Column(db.DateTime, default=datetime.datetime.utcnow())    songs = db.relationship('Song', cascade="all,delete", backref=db.backref('user', lazy='joined'), lazy='dynamic')    def __init__(self, email, password):        self.email = email        self.set_password(password)    def __repr__(self):        return '<User %r>' % self.email    def set_password(self, password):        self.password_hash = generate_password_hash(password)    def check_password(self, password):        return check_password_hash(self.password_hash, password)    def is_authenticated(self):        return True    def is_active(self):        return True    def is_anonymous(self):        return False    def get_id(self):        return str(self.email)def init_db():    db.create_all()    # Create a test user    new_user = User('a@a.com', 'aaaaaaaa')    new_user.display_name = 'Nathan'    db.session.add(new_user)    db.session.commit()    new_user.datetime_subscription_valid_until = datetime.datetime(2019, 1, 1)    db.session.commit()if __name__ == '__main__':    init_db()

In your case, require to add following code into __init__.py:

from models import User, Role@app.shell_context_processordef make_shell_context():    return dict(db=db, User=User, Role=Role)

then you do your previous works, it's all work.