How connect Postgresql database with sqlalchemy python

Ask Time：2020-05-31T16:49:58 Author：Bell9999

I'm currently writing an program using Flask python. But I can not connect my database with my program. I'm use Postgresql for database.

import os

from sqlalchemy import create_engine

from sqlalchemy.orm import scoped_session, sessionmaker

engine = create_engine(os.getenv("DATABASE_URI"))

db = scoped_session(sessionmaker(bind=engine))

This is the code what I'm using for it, But it didn't work. So please help me to connect my database

This is the error message that what I have got, Error message

Author:Bell9999，eproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/62113733/how-connect-postgresql-database-with-sqlalchemy-python

user16298377 :

Configure database string\nfrom sqlalchemy import create_engine\nengine = create_engine('postgresql+psycopg2://user:password@hostname/database_name')\n\nConnect db then:\nimport psycopg2\nconn_string = "host='localhost' dbname='my_database' user='postgres' password='secret'"\nconn = psycopg2.connect(conn_string)\n",

2021-07-16T13:31:04

Akshay Jain :

db.py File which contains db connection(postgres url)\n\nfrom flask import Flask\nfrom flask_sqlalchemy import SQLAlchemy\n\napp = Flask(__name__)\napp.config['SQLALCHEMY_DATABASE_URI'] = 'postgres://postgres:postgres@localhost/DB_NAME'\n\ndb = SQLAlchemy(app)\n\n\napp.py This is your main file database tables will create when your server hits the first request.\n\nfrom db import *\[email protected]_first_request\ndef before():\n db.create_all()\n\nenter code here......\n\n\n\ntable_structure.py This file contains your table structure\n\nfrom db import db\nclass UserProjects(db.Model):\n id = db.Column(db.Integer, primary_key=True)\n name = db.Column(db.String(140), nullable=False)\n\n",

2020-05-31T12:42:14

How connect Postgresql database with sqlalchemy python