I recently needed a performant way to manage a tree, meaning using MPTT, nested sets etc.

I looked at the following libraries, which integrate with SQLAlchemy. These are my notes, some of which seem to be outdated now.

https://github.com/ITCase/sqlalchemy_mptt/

• No features for querying
• Injects fields like parent_id, children into the model by itself, without allowing customization.
• It’s rebuild() is not able to init a tree from scratch.

https://sqlalchemy-orm-tree.readthedocs.org/

• Integrating into the class-based ORM mapper is messy (pr accepted)
• No rebuild() feature at all (pr accepted)
• Has bugs when used with ORM attributes are diverging from table column names
• BIG PLUS: can detect and handle tree moves if attributes on an existing node change.
• Does not support keeping a sort order around.

https://bitbucket.org/angri/sqlamp/

• Seems to have a working rebuild()
• Can sort of integrate with the class-based ORM mapper setup (although it seems it would need to be globally)
• tree_recursive_iterator() for querying a tree.
• To move a subtree, we need to call special move() methods.

sqlamp and sqlalchemy-orm-tree seem to share a lot of ideas/APIs.

sqlamp seems to be the most most stable / actively developed, although sqlalchemy-orm-tree makes a good impression, too, and the tree move detection is so helpful that I decided to go with it.