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Tracking Modifications
======================
.. warning::
Tracking changes adds significant overhead. In most cases, you'll be better served by
using `SQLAlchemy events`_ directly.
.. _SQLAlchemy events: https://docs.sqlalchemy.org/core/event.html
Flask-SQLAlchemy can set up its session to track inserts, updates, and deletes for
models, then send a Blinker signal with a list of these changes either before or during
calls to ``session.flush()`` and ``session.commit()``.
To enable this feature, set :data:`.SQLALCHEMY_TRACK_MODIFICATIONS` in the Flask app
config. Then add a listener to :data:`.models_committed` (emitted after the commit) or
:data:`.before_models_committed` (emitted before the commit).
.. code-block:: python
from flask_sqlalchemy.track_modifications import models_committed
def get_modifications(sender: Flask, changes: list[tuple[t.Any, str]]) -> None:
...
models_committed.connect(get_modifications)
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