First create the db object using the SQLAlchemy constructor. Pass a subclass of either DeclarativeBase or DeclarativeBaseNoMeta to the constructor. from flask import Flask from flask_sqlalchemy import SQLAlchemy from sqlalchemy.orm import DeclarativeBase class Base(DeclarativeBase): pass db = SQLAlchemy(model_class=Base)

October 24, 2025 - This example demonstrates a Flask application where users can submit data through a form. The submitted data is stored in a database using SQLAlchemy, displayed on a separate page, and can be deleted when needed.

January 9, 2016 - Learn how to integrate SQLAlchemy with Flask for robust database management in your web applications.

In this section, we will study the ORM technology of Flask-SQLAlchemy and build a small web application.

Flask-SQLAlchemy does not change how SQLAlchemy works or is used. See the SQLAlchemy documentation to learn how to work with the ORM in depth.

To define your models, just subclass the Base class that was created by the code above. If you are wondering why we don’t have to care about threads here (like we did in the SQLite3 example above with the g object): that’s because SQLAlchemy does that for us already with the scoped_session.

October 21, 2025 - Learn how to use Flask-SQLAlchemy to manage databases in Flask. Create models, perform CRUD operations, and build scalable Python web apps.

The first is Flask-SQLAlchemy, an extension that provides a Flask-friendly wrapper to the popular SQLAlchemy package, which is an Object Relational Mapper or ORM. ORMs allow applications to manage a database using high-level entities such as ...

February 17, 2025 - Here, from the “flask_sqlalchemy” module, we are importing the “SQLAlchemy” class. Then we are creating a new instance and store it in the “db” variable. Also, we are setting the “SQLALCHEMY_DATABASE_URI” configuration variable to be the URI of our SQLite database, and then our Flask application knows which database it should use.

February 26, 2025 - Python 3.6+ and pip: Flask-SQLAlchemy requires Python 3.6 or higher. We’ll also install everything we need with pip. MySQL: The steps in this guide are tested with MySQL installed (on Ubuntu for WSL). Basic knowledge of Python and Flask: This tutorial requires familiarity with virtual environments, Flask application structure, and basic terminal commands.

March 31, 2022 - Building a Simple Flask App With SQLAlchemy — Andres Berejnoi Today’s post is about integrating a database, such as MySQL to a Python web application. I will use SQAlchemy and Flask together for …

February 25, 2024 - Because we installed SQLAlchemy and the Flask extension Flask-SQLAlchemy at the start of this tutorial, we can go straight into using them now. We need to set up a database, open a connection to it, and associate this connection with our web application.

It aims to simplify using SQLAlchemy with Flask by providing useful defaults and extra helpers that make it easier to accomplish common tasks.

March 7, 2026 - Werkzeug and Jinja2: Flask uses Werkzeug for handling HTTP requests and responses and Jinja2 for creating dynamic HTML templates. Routing: It provides an easy routing system where URLs are mapped to Python functions using decorators. Flexible Database Choice: It does not include a built-in ORM, allowing developers to use tools like SQLAlchemy or raw SQL based on project requirements.

May 11, 2023 - Flask SQLAlchemy provides a simple and intuitive way to define these classes as Python classes, allowing developers to work with databases using familiar Python syntax and object-oriented programming concepts.

May 5, 2023 - Flask is an excellent tool for creating REST applications. For a multi-part series of tutorials about using Flask, Connexion, and SQLAlchemy to create REST applications, check out Python REST APIs With Flask, Connexion, and SQLAlchemy.

You may see uses of Model.query or session.query to build queries. That query interface is considered legacy in SQLAlchemy.

An ORM converts data between incompatible systems (object structure in Python, table structure in SQL database). SQLAlchemy is basically a bridge between Python and a SQL database. Flask-SQLAlchemy is an extension for Flask that adds SQLAlchemy to your Flask app.