Information Modeling and Relational Databases, 2nd Edition

13.7. Transactions and Concurrency

Operations affecting data in a DBMS are contained in transactions. A transaction may be composed of many individual actions, which, in some sense, can be considered together as an atomic unit of activity. In order to preserve the integrity of the database, we can make positive decisions about whether to accept the results of a unit of activity or not. The corresponding database operations are commit, which makes the results permanent, and rollback, which aborts the activity and removes the results of the transaction, leaving the database in the state it was in before the transaction began. In some situations, the commit or rollback is carried out implicitly, depending on whether a program terminates normally ...