Why do I get a NameError when importing external DB models into my Flask App?

Question

I'm trying to split out my models into a separate file as it's getting too large to manage. I've followed this but I am getting a NameError despite having run db.create_all():

NameError: name 'importsTable' is not defined

# stack_app.py
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from stack_dbmodels import db
from stack_dbmodels import importsTable
from datetime import datetime

app = Flask(__name__)
app.secret_key = 'secretsquirrel'

app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///stack_newAppCsv.db'
db.init_app(app)

@app.route('/', methods=['GET'])
def stack():
    username = "username"
    new_user = importsTable(username)
    db.session.add(new_user)
    db.session.commit()
    return "Done!"

if __name__ == "__main__":
    app.run(debug = True, port=8080)

My models file:

# stack_dbmodels.py
from flask_sqlalchemy import SQLAlchemy

db = SQLAlchemy()

class importsTable(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(80))

    def __init__(self, username):
        self.username = username

    def __repr__(self):
        return '<Import {0}>'.format(self.username)

Please provide a [mcve]. I'm afraid these incomplete chunks of code aren't enough to solve this. — ForceBru, Mar 05 '18 at 13:11
it might be due to your folder structure.could you share your project tree — PythonUser, Mar 05 '18 at 13:56
Both Python files are in the top directory, as is the DB file that was created. — Johnny John Boy, Mar 05 '18 at 14:02

Johnny John Boy · Accepted Answer · 2018-03-07T06:40:44.713

The problem was mainly with the context of the app but during my tests there were a couple of gotchas I found. Key to make the above work was:

When I reference importsTable it wasn't initially defined unless I did:

from stack_dbmodels import db
from stack_dbmodels import importsTable

And whilst the .db file was created, the context wasn't correct so it couldn't create the actual importsTable so I added the following and problem solved, the key bit was "with app.app_context()":

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

Final working code was:

# stack_app.py
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from stack_dbmodels import db
from stack_dbmodels import importsTable
from datetime import datetime

app = Flask(__name__)
app.secret_key = 'secretsquirrel'

app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///stack_newAppCsv.db'
db.init_app(app)
with app.app_context():
    db.create_all()

@app.route('/', methods=['GET'])
def stack():
    username = "username"
    new_user = importsTable(username)
    db.session.add(new_user)
    db.session.commit()
    return "Done!"

if __name__ == "__main__":
    app.run(debug = True, port=8080)

Why do I get a NameError when importing external DB models into my Flask App?

1 Answers1