How do I handle transaction rollback in SQLAlchemy?

How do I handle transaction rollback in SQLAlchemy?

In SQLAlchemy, you can handle transaction rollbacks using the rollback() method of the session object. If an error occurs during a transaction, you can call this method to revert any changes made during that transaction.

Can you show me a code example of that?

Sure! Here's a simple example:

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker

engine = create_engine('sqlite:///:memory:')
Session = sessionmaker(bind=engine)
session = Session()

try:
    # Your database operations here
    session.commit()
except Exception as e:
    session.rollback()
    print(f'Error occurred: {e}')
finally:
    session.close()

What happens if I don't call rollback?

If you don't call rollback() after an error, the session will remain in a 'dirty' state, and any subsequent operations may fail until the session is cleared or closed.