transactions

I have concurrent reads and writes and am seeing unexpected behavior: dirty reads, non-repeatable reads, or phantom rows. I need to understand PostgreSQL isolation levels and when to use each.

FastAPI database dependency using SQLAlchemy async session. Need automatic transaction rollback when route handlers raise exceptions, and ensure sessions are always closed without leaking connections....

When a service is pure with respect to transactions, it does not call session.commit() or session.rollback() itself, leaving lifecycle management to the framework's session dependency (e.g. FastAPI's ...

When implementing multi-step API flows (e.g. upload then set permissions then insert), cleanup of earlier steps on later failure must cover three distinct failure modes: non-2xx HTTP responses (checke...