Flask Framework Cookbook - Second Edition

There's more...

Sometimes, you may want a single SQLAlchemy db instance to be used across multiple applications, or create an application dynamically. In such cases, we might not prefer to bind our db instance to a single application. Here, we will have to work with the application context to achieve the desired outcome.

In this case, we will register our application with SQLAlchemy differently as follows:

from flask import Flask 
from flask_sqlalchemy import SQLAlchemy 
 
db = SQLAlchemy() 
 
def create_app(): 
    app = Flask(__name__) 
    db.init_app(app) 
    return app 

The preceding approach can be taken up while initializing the app with any Flask extension, and is very common when dealing with real-life applications.

Now, all the operations that were ...