The Oracle RDBMS handles transaction roll back and recovery, but ABL transaction scoping rules apply.

In ABL, transactions end at the end of the outermost block where an update takes place. When a transaction that updates an Oracle database ends successfully, ABL sends a COMMIT to the Oracle instance. If you interrupt the transaction, ABL sends a ROLLBACK to the Oracle instance.

The Oracle database supports "deferred constraints" which are enforced at a transaction boundary. If a deferred constraint violation occurs at a transaction boundary, the transaction is rolled back and the application is terminated.

See Develop ABL Applications for more information on how ABL handles transactions and error conditions.