The update staging table contains two columns for every primary-key column specified in the corresponding replication definition, one each for the column data before and after a change.
The update staging table also contains a column for each nonprimary-key column specified in the replication definition. To track whether changes have been made to data in these nonprimary-key columns, the update staging table contains one or more bitmap columns. Each bitmap column is of type
int and can therefore track 32 non-primary key columns. A value of 1 constitutes a dirty bit, indicating that data has changed in the column corresponding to that bit position.
Note: The before-change and bitmap columns of the update staging table are not visible in the SQL Transformation project in Sybase IQ InfoPrimer.