[SQLAlchemy] flush vs commit

What's the difference between flush() and commit()?

 

 

- flush

  : The session object registers transaction operations with session.add(), but doesn't yet communicate them to the database until session.flush() is called.

session.flush() communicates a series of operations to the database (insert, update, delete). The database maintains them as pending operations in a transaction. The changes aren't persisted permanently to disk, or visible to other transactions until the database receives a COMMIT for the current transaction (which is what session.commit() does).

 

- commit 

  : session.commit() commits (persists) those changes to the database.

 

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https://stackoverflow.com/questions/4201455/sqlalchemy-whats-the-difference-between-flush-and-commit