Flask-SQLAlchemy app fails to create tables

Question

Context: I'm creating my first flask web app as a twitter clone in which developers can post "dev logs" to a game they're developing.

From what I've learned in this tutorial, I've repackaged my app to become four python modules. I'm still a bit confused and I think I got some things wrong, but when I run the program through the script below:

from home import app

if __name__ == "__main__":
    app.run(debug=True)

Where home is the name of my flask app. Running this outputs this error:

Traceback (most recent call last):
  File "run.py", line 1, in <module>
    from home import app
  File "/Users/AdityaD/iCloud Drive (Archive)/Desktop/DevlogIO/home/__init__.py", line 11, in <module>
    from home import routes
  File "/Users/AdityaD/iCloud Drive (Archive)/Desktop/DevlogIO/home/routes.py", line 10, in <module>
    db.session.commit()
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/orm/scoping.py", line 153, in do
    return getattr(self.registry(), name)(*args, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/orm/session.py", line 943, in commit
    self.transaction.commit()
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/orm/session.py", line 467, in commit
    self._prepare_impl()
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/orm/session.py", line 447, in _prepare_impl
    self.session.flush()
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/orm/session.py", line 2254, in flush
    self._flush(objects)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/orm/session.py", line 2381, in _flush
    transaction.rollback(_capture_exception=True)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/util/langhelpers.py", line 66, in __exit__
    compat.reraise(exc_type, exc_value, exc_tb)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/util/compat.py", line 249, in reraise
    raise value
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/orm/session.py", line 2345, in _flush
    flush_context.execute()
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/orm/unitofwork.py", line 395, in execute
    rec.execute(self)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/orm/unitofwork.py", line 560, in execute
    uow
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/orm/persistence.py", line 181, in save_obj
    mapper, table, insert)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/orm/persistence.py", line 866, in _emit_insert_statements
    execute(statement, params)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 948, in execute
    return meth(self, multiparams, params)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/sql/elements.py", line 269, in _execute_on_connection
    return connection._execute_clauseelement(self, multiparams, params)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1060, in _execute_clauseelement
    compiled_sql, distilled_params
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1200, in _execute_context
    context)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1413, in _handle_dbapi_exception
    exc_info
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/util/compat.py", line 265, in raise_from_cause
    reraise(type(exception), exception, tb=exc_tb, cause=cause)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/util/compat.py", line 248, in reraise
    raise value.with_traceback(tb)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1193, in _execute_context
    context)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/sqlalchemy/engine/default.py", line 509, in do_execute
    cursor.execute(statement, parameters)
sqlalchemy.exc.OperationalError: (sqlite3.OperationalError) no such table: user [SQL: 'INSERT INTO user (username, password) VALUES (?, ?)'] [parameters: ('admin', 'admin123')] (Background on this error at: http://sqlalche.me/e/e3q8)

This is my init file:

from flask import Flask
from flask_session import Session

# Set's up the app with the given name 
app = Flask(__name__) 
# Secret key for sessions
app.config['SECRET_KEY'] = 'eb02cfb5079a2b6bdeb8bddb69ca937b' 
# Sets up config for database with SQLite, which is easy to set up. 
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///site.db'

from home import routes
from home.models import *

db.create_all()

Below is routes.py:

from flask import render_template, url_for, flash
import os, datetime
from home import app
from home.models import db

#dummy data
import home.models
theUser = home.models.User(username='admin', password='admin123')
db.session.add(theUser)
db.session.commit()
admin = home.models.User.query.filter_by(username='admin').first()
zombies = home.models.Games(game='Shoot Zombies!', user_id=admin.id)
ball = home.models.Games(game='Bounce & Ball', user_id=admin.id)
db.session.add(zombies)
db.session.add(ball)
db.session.commit()

def getCurrentUser():
    return admin

from home import posts

@app.route("/", methods=['GET', 'POST'])
def index():
    form = posts.WriteLog()
    if form.validate_on_submit():
        username = current_user.username
        post = form.devLog.data
        game = Games.query.filter_by(game=form.gameSelect.data).first().id
        title = form.title.date
        newPost = Post(title=title, game_id=game, content=post)
        return render_template("index.html", form=form, data=Post)
    return render_template("index.html", form=form, data=Post)

Below is models.py:

from home import app
from flask_sqlalchemy import SQLAlchemy 
import os, datetime

# Sets up SQL Database
db = SQLAlchemy(app)

### Database Stuff ###
# Creates a table for the user

class User(db.Model):
    __tablename__ = "user"
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(20), nullable=False)
    password = db.Column(db.String(20), nullable=False)
    games = db.relationship('Games', backref="user", lazy=True)

    def __repr__(self):
        return f"User('{self.username}', '{self.password}', '{self.games}')"

# Creates a table for games
class Games(db.Model):
    __tablename__ = "game"
    id = db.Column(db.Integer, primary_key=True)
    game = db.Column(db.String(40), nullable=False)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False) 
    logs = db.relationship('Post', backref="game", lazy=True)

    def __repr__(self):
        return f"Game('{self.game}', '{self.logs}')"

class Post(db.Model):
    __tablename__ = "post"
    id = db.Column(db.Integer, primary_key=True)
    title = db.Column(db.String(100), nullable=False)
    date_posted = db.Column(db.DateTime, nullable=False, default=datetime.datetime.utcnow)
    game_id = db.Column(db.Integer, db.ForeignKey('game.id'), nullable=False)
    content = db.Column(db.Text, nullable=False)

    def __repr__(self):
        return f"Post('{self.title}', '{self.date_posted}', '{self.game_id}', '{self.content}')"

And posts.py is just an app which manages the forms. As I understand it, the User table was not created. However, I have run the db.create_all() command in the init file. Help would be appreciated!

UPDATE: Now I have a new bug.

sqlalchemy.exc.ProgrammingError: (sqlite3.ProgrammingError) SQLite objects created in a thread can only be used in that same thread.The object was created in thread id 140734986048960 and this is thread id 123145577107456 [SQL: 'SELECT post.id AS post_id, post.title AS post_title, post.date_posted AS post_date_posted, post.game_id AS post_game_id, post.content AS post_content \nFROM post \nWHERE ? = post.game_id'] [parameters: [{'%(4536059552 param)s': 1}]] (Background on this error at: http://sqlalche.me/e/f405)

For reference, this is my index.html file:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>DevlogIO</title>
    <link rel="stylesheet" href="{{ url_for('static', filename='style.css') }}">
</head>
<body>
    <div id="container">
        <h1>Devlog IO</h1>
        <h2>Home</h2>
        <p>See the progress of your favorite developers, and discover new and rising game developers!</p>
        <div>
            <form action="" method="POST">
                {{ form.hidden_tag() }}
                <fieldset>
                    <legend>What was your progress for today?</legend>
                    <div>
                        {{ form.gameSelect(class="") }}
                    </div>
                    <br>
                    <div>
                        {{ form.title.label(class="") }}
                        {{ form.title(class="")  }}
                    </div>
                    <br>
                    <div>
                        {{ form.devLog.label(class="") }}
                        {{ form.devLog(class="")  }}
                    </div>
                    <br>
                    <div>
                        {{ form.submit(class="") }}
                    </div>  
                    <br>  
                </fieldset>
            </form>
        </div>
        <hr>
        <div id="stream">
                {% for post in data.query.all() %}
                    <fieldset>
                        <p><strong>{{ post.title }}, {{ form.gameSelect.data }}</strong></p>
                        <p><i>by {{ post.game_id }}</i></p>
                        <p><i>{{ post.date_posted }}</i></p>
                        <p>{{ post.content }}</p>    
                    </fieldset>
                    <br>
                {% endfor %}
        </div>

    </div>

    <script src="{{ url_for('static', filename='script.js') }}"></script>
</body>
</html>

user10539474 · Accepted Answer · 2018-11-13 13:27:09Z

1

in traceback in first line is said that error appears on line 11: from home import routes Your app even didn't get to db.create_all() and fails on import in which your references to db object that does ot exist yet. Try to put db.create_all() into routes.py

answered Nov 13, 2018 at 13:27

user10539474

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1 Comment

GM Crow Over a year ago

This seemed to do it.However, I now have an entirely new bug: sqlalchemy.exc.ProgrammingError: (sqlite3.ProgrammingError) SQLite objects created in a thread can only be used in that same thread.The object was created in thread id 140734986048960 and this is thread id 123145577107456 [SQL: 'SELECT post.id AS post_id, post.title AS post_title, post.date_posted AS post_date_posted, post.game_id AS post_game_id, post.content AS post_content \nFROM post \nWHERE ? = post.game_id'] [parameters: [{'%(4536059552 param)s': 1}]] (Background on this error at: sqlalche.me/e/f405)

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