A copy of the old and new state of each row affected by each data modification statement is written to the transaction log. This means that if you begin a transaction by issuing the begin transaction command, realize you have made a mistake, and roll the transaction back, the database is restored to its previous condition.
You cannot roll back changes made on a remote Adaptive
Server by means of a remote procedure call (RPC).
An exception is writetext, when the select/into bulkcopy database option is set to false.
The default mode of operation for writetext does not log the transactions. This avoids filling up the transaction log with the extremely long blocks of data that text and image fields may contain. The with log option to the writetext command must be used to log changes made with this command.
A more complete discussion of transactions appears in Chapter 19, “Transactions: Maintaining Data Consistency and Recovery.”
