How can I use eager loading in Flask-SQLAlchemy?

How can I use eager loading in Flask-SQLAlchemy?

Eager loading in Flask-SQLAlchemy allows you to load related objects in a single query, improving performance. You can use the joinedload or subqueryload options when querying your models.

Can you show me an example of how to implement it?

Sure! Here's a simple example:

from flask_sqlalchemy import SQLAlchemy
from sqlalchemy.orm import joinedload

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    posts = db.relationship('Post', backref='author')

class Post(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'))

# Eager loading posts when querying users
users = User.query.options(joinedload(User.posts)).all()

What are the benefits of using eager loading?

The main benefits of eager loading are reduced database queries, improved performance, and avoiding the N+1 query problem, which can slow down your application.