Use the @BEFORE function to return the before image of the specified source column.
When using this parameter, use the GETUPDATEBEFORES parameter in the Extract parameter file to capture before images from the transaction record, or use it in the Replicat parameter file to use the before image in a column mapping or filter. If using the Conflict Resolution and Detection (CDR) feature, you can use the GETBEFORECOLS option of TABLE. To use these parameters, the specified column must be present in the transaction log.
If the database only logs values for changed columns, make certain the required column values are available by enabling supplemental logging for those columns. Alternatively, you can use the FETCHCOLS or FETCHCOLSEXCEPT option of the TABLE parameter. The fetch option involves additional processing overhead.
Example
@BEFORE (quantity)