@apr Ecto itself doesn’t “undo” the operations, rather it opens a transaction and then all operations within that transaction will be rolled back by the database unless the transaction is committed.

Gotcha! Thanks a lot @OvermindDL1!

Edit: I was also wondering, if you use a Multi.run to actually update the DB, does the update get rolled back when some other operation down the line fails? If so, how does Ecto figure out which Multi runs update the DB and which ones don’t (In order to rollback any updates on failure)?

In order for an operation in a Multi.run block to be included in the transaction must the run block use the Repo argument passed from the earlier Multi step or can it call a function that makes arbitrary Repo calls while not using the repo passed in from the Multi? This could be such as calling Repo.one, Repo.insert, or something like that