'sqlalchemy.exc.NoSuchModuleError: Can't load plugin: sqlalchemy.dialects:postgres

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)
pythonpostgresqlsqlalchemyflask-sqlalchemypsycopg2


Solution 1:[1]

The URI should start with postgresql:// instead of postgres://. SQLAlchemy used to accept both, but has removed support for the postgres name.

Solution 2:[2]

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.

Solution 3:[3]

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

Solution 4:[4]

# production or dev DB
try:
    prodURI = os.getenv('DATABASE_URL')
    prodURI = prodURI.replace("postgres://", "postgresql://")
    app.config['SQLALCHEMY_DATABASE_URI'] = prodURI

except:
    app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql:///MYDATABASE'

I tried all the above answers, but only this worked for me. I followed Heroku's official suggestion (mentioned in previous comments), but no luck. I think taking off the 1 at the end of replace() may have helped.

Solution 5:[5]

To fix this, rename postgres:// in the URL to postgresql+psycopg2://.

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 davidism
Solution 2 davidism
Solution 3 davidism
Solution 4 Kaitlin Berryman
Solution 5

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