How do I manage transactions in Flask with SQLAlchemy?

How do I manage transactions in Flask with SQLAlchemy?

You can manage transactions in Flask with SQLAlchemy using the session object. You typically start a transaction, make your changes, and then commit or rollback based on success or failure.

Can you show me a code example?

Sure! Here's a simple example:

from flask import Flask
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///example.db'
db = SQLAlchemy(app)

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(50))

@app.route('/add_user/<name>')
def add_user(name):
    new_user = User(name=name)
    try:
        db.session.add(new_user)
        db.session.commit()
    except:
        db.session.rollback()
        return 'Error occurred!'
    return 'User added!'

This code adds a user to the database and handles transactions.

What happens if there's an error during the transaction?

If there's an error, the except block will execute, rolling back the session to ensure the database remains consistent.