In the field of databases in computer science, a transaction log (also transaction journal, database log, binary log or audit trail) is a history of actions executed by a database management system used to guarantee ACID properties over crashes or hardware failures.
Physically, a log is a file listing changes to the database, stored in a stable storage format.
Additionally, all transactions that are already committed but whose changes were not yet materialized in the database are re-applied.
This term is not to be confused with other, human-readable logs that a database management system usually provides.
In database management systems, a journal is the record of data altered by a given process.