I'm trying to connect to a Postgres database with SQLAlchemy. I've installed psycopg2. However, I get the error sqlalchemy.exc.NoSuchModuleError: Can't load plugin: sqlalchemy.dialects:postgres. How do I configure SQLAlchemy to connect to PostgreSQL?
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
app = Flask(__name__)
app.config["SQLALCHEMY_DATABASE_URI"] = "postgres://username@localhost:5432/template1"
db = SQLAlchemy(app)
The problem in heroku have been resolved by using simple python url replace code
import os
import re
uri = os.getenv("DATABASE_URL") # or other relevant config var
if uri and uri.startswith("postgres://"):
uri = uri.replace("postgres://", "postgresql://", 1)
# rest of connection code using the connection string `uri`
source : https://help.heroku.com/ZKNTJQSK/why-is-sqlalchemy-1-4-x-not-connecting-to-heroku-postgres
SQLAlchemy 1.4 removed the deprecated postgres dialect name, the name postgresql must be used instead now. The dialect is the part before the :// in the URL. SQLAlchemy 1.3 and earlier showed a deprecation warning but still accepted it.
To fix this, rename postgres:// in the URL to postgresql://.
This error currently shows up when working with Heroku, which uses postgres in the DATABASE_URL they provide, which you probably use for SQLALCHEMY_DATABASE_URI. To work around this until they update it, update the variable in the Heroku dashboard to use postgresql.
The URI should start with postgresql:// instead of postgres://. SQLAlchemy used to accept both, but has removed support for the postgres name.