(1) In SQL replication, the content of a replication source-table column before it is updated by a transaction. The content is recorded in a change data (CD) table or in a database log or journal. See also after-image, before-value.
(2) The contents of a record in a physical file before the data is changed by a write, an update, or a delete operation.
(3) A record of the contents of a data element before it is changed. Before images are used to backout incomplete or incorrect changes in the event of a failure.