Make a multi-step write one transaction

One call creates the order, another adds its line items. If the second one fails, the order is left half-made.

Beginner to intermediateRead 5 minDoing: under an hour6 steps

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What you'll have at the end

A write that either saves the order with all its items or saves nothing at all, tested by forcing a mid-write failure

Before you start

You need

A SQLAlchemy-backed endpoint that already creates an order in one call and adds its line items in a second, each ending with its own commit.

Not covered

Coordinating this same write across two separate databases or external services, which calls for a distributed transaction protocol, not a single session block.

Leans on

ORM and Database Abstraction Tools Cheat Sheetthe Transactions table lays out the session patterns this recipe builds the fix from
Database Transactions and Concurrency Control Cheat Sheetexplains what atomicity and rollback actually guarantee underneath the ORM's transaction block

6 steps

Checked 18 Aug 2026

Part of the ORM and Database Abstraction Tools cookbook