If that last paragraph sounded like total gibberish to you, you are not alone. Within the actual 'application context' is where we'll call create_all(), which we'll cover in a bit. We accomplish this by calling db.init_app() within create_app(), and passing app as the parameter. Even though we've set our db object globally, this means nothing until we initialize it after creating our application. Inside of create_app(), on the other hand, contains the line db.init_app(app). Note the presence of db and its location: this our database object being set as a global variable outside of create_app(). The most basic _init_.py file for Flask applications using Flask-SQLAlchemy should look like this: from flask import FlaskĪpp = Flask(_name_, instance_relative_config=False)ĭb.create_all() # Create sql tables for our data models If you're unfamiliar with the term, you're going to find this tutorial to be confusing and pretty much useless. Initiating Flask-SQLAlchemyĪs always, we're going to use the Flask Application Factory method for initiating our app. We will never have to create engines, sessions, or connections. If you're into some next-level database shit, there are a few other pro-mode configuration variables which you can find here.īy using the exact naming conventions for the variables above, simply having them in our config file will automatically configure our database connections for us. ![]() Those are the big ones we should worry about. SQLALCHEMY_TRACK_MODIFICATIONS: Honestly, I just always set this to 'False,' otherwise an obnoxious warning appears every time you run your app reminding you that this option takes a lot of system resources.This follows the standard convention: SQLALCHEMY_ECHO: When set to 'True', Flask-SQLAlchemy will log all database activity to Python's stderr for debugging purposes. SQLALCHEMY_DATABASE_URI: the connection string we need to connect to our database.There are a few variables here which are specific to Flask-SQLAlchemy: ![]() As is standard, we'll be using a class defined in config.py to handle our Flask config: There are a few essential configuration variables we need to set upfront before interacting with our database. Given the ease-of-use and one-size-fits-all nature of Flask-SQLAlchemy, it's no wonder that the library has been the de facto database library of choice for Flask since the very beginning (seriously, is there even another option?) Configuring Flask-SQLAlchemy For Your Application Regardless of what your database of choice might be, Flask-SQLAlchemy will ensure that the models we create in Python will translate to the syntax of our chosen database. ![]() ![]() Similar to the core SQLAlchemy package, Flask-SQLAlchemy provides an ORM for us to modify application data by easily creating defined models. SQLALCHEMY_TRACK_MODIFICATIONS = False config.py SQLALCHEMY_DATABASE_URI = environ.get("SQLALCHEMY_DATABASE_URI") """Flask configuration variables."""īasedir = path.abspath(path.dirname(_file_)) Like most major Python libraries, SQLAlchemy has been ported into a version specifically compatible with Flask, aptly named Flask-SQLAlchemy. Demystifying Flask’s “Application Factory”īy now you're surely familiar with the benefits of Python's SQLAlchemy library: the all-in-one solution for basically anything database related.Bundle & Serve Frontend JS & Styles in Flask.Connect Flask to a Database with Flask-SQLAlchemy.Flask User Accounts & Authentication in with Flask-Login.User Session Data with Flask-Session & Redis.
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