Flask SQLAlchemy import DB import

Question

I am using flask with SQLAlchemy, after set all configuration setting I got db import error on model.

ImportError: cannot import name 'db'

my main app __init__

from flask_api import FlaskAPI
from flask_sqlalchemy import SQLAlchemy
import os
import json
from flask import Flask
from flask_pymongo import PyMongo
from flask import request

from app.test.controllers import test


def create_app(config_name):
    app = FlaskAPI(__name__)
    CORS(app)
    app.config.from_object(os.environ['APP_SETTINGS'])
    db = SQLAlchemy(app)
    from app.test.controllers import test
    app.register_blueprint(test)

my controller and model in app/test/test.py and model.py

test.py

from flask import Blueprint, request, redirect, url_for
import json
from flask_sqlalchemy import SQLAlchemy

from app.test.model import TestModel

test = Blueprint('test', __name__, url_prefix='/api/v1')


@test.route('/test/store', methods=['POST'])
def store():
    return json.dumps({'success':True}), 200, {'ContentType':'application/json'}

my model.py

from app import db

class TestModel(db.Model):
    __tablename__ = 'user_profiles'
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(255), unique=False)
    email= db.Column(db.String(255), unique=False)


    def __init__(self, name=None, email=None):
        self.name = name
        self.email = email

    def __repr__(self):
        return '<User %r>' % (self.name, self.email)

noslenkwah · Accepted Answer · 2019-05-08 20:58:47Z

3

You are using the Flask factory method so initialize SqlAlchemy in your model and import it to your __init__.py file

So model.py becomes

from flask_sqlalchemy import SQLAlchemy    
db = SQLAlchemy()

class TestModel(db.Model):
    __tablename__ = 'user_profiles'
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(255), unique=False)
    email= db.Column(db.String(255), unique=False)


    def __init__(self, name=None, email=None):
        self.name = name
        self.email = email

    def __repr__(self):
        return '<User %r>' % (self.name, self.email)

Then in __init__.py it becomes

from flask_api import FlaskAPI
from model import db
import os
import json
from flask import Flask
from flask_pymongo import PyMongo
from flask import request

from app.test.controllers import test


def create_app(config_name):
    app = FlaskAPI(__name__)
    CORS(app)
    app.config.from_object(os.environ['APP_SETTINGS'])
    db.init_app(app)
    from app.test.controllers import test
    app.register_blueprint(test)

edited May 8, 2019 at 20:58

noslenkwah

1,7542 gold badges17 silver badges31 bronze badges

answered May 8, 2019 at 20:43

azdonald

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3 Comments

vipin Over a year ago

hi, so if there is multiple models. how can i import db

vipin Over a year ago

i want single init file which creates the db instance and then any model can access it.

azdonald Over a year ago

If you want multiple model files, then you can put them a package(lets call the package models) and in the init.py file of the models package, you create the db object and import it where ever its needed.

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