How do I create SQLAlchemy models in a Flask app?

How do I create SQLAlchemy models in a Flask app?

To create SQLAlchemy models in a Flask app, you first need to install Flask-SQLAlchemy. Then, define your models by creating classes that inherit from db.Model. Each class represents a table in your database.

Can you show me an example of a model?

Sure! Here's a simple example:

from flask_sqlalchemy import SQLAlchemy

db = SQLAlchemy()

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(80), unique=True, nullable=False)
    email = db.Column(db.String(120), unique=True, nullable=False)

What if I want to add relationships between models?

You can define relationships using the relationship function. For example:

class Post(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    title = db.Column(db.String(100), nullable=False)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'))
    user = db.relationship('User', backref='posts')

How do I create the database tables from these models?

You can create the database tables by running db.create_all() after initializing your app and database. Make sure to set up your app context!