Whenever audit data is created, the current database transaction ID will be recorded in the _transaction-id field and within a transaction, for auditable events, the _transaction-sequence will be updated to provide the order in which things happened within the transaction.

This is useful in identifying what occurred within the bounds of a single database transaction. It could likely be used when looking at a specific field value change to see what other information was updated in the same transaction that could have impacted the new value of the field.

Note that transaction IDs can loop back to zero, so take care when reporting by transaction ID across multiple transactions. The date and time should be used with the transaction ID to get a more accurate sequencing of events.

Note also that transaction IDs are not unique to a database.