Overview

Flask-SQLAlchemy 3.1, released on September 12, 2023, fixes bugs and improves SQLAlchemy 2.0 compatibility.

Main Features

SQLAlchemy 2.0 compatibility

Integration with the SQLAlchemy 2.0 query style is complete, using select() instead of query.

python 
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy import select

db = SQLAlchemy()

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

# SQLAlchemy 2.0 style
users = db.session.execute(select(User)).scalars().all()

Bug fixes

Several fixes improve session management and connection cleanup at the end of requests.

python 
from flask import Flask
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///app.db'
db = SQLAlchemy(app)

# Session is automatically cleaned up
# at end of request (improved in 3.1)

Sources