The following figure shows a mapping that the Incremental Load Wizard creates when you select the Incremental Load option:

The Incremental Load mapping uses Lookup and Expression transformations to compare source data against existing target data. When you step through the Slowly Changing Dimensions Wizard, you enter the lookup conditions and source columns that you want the Integration Service to compare against the existing target. The Designer creates additional columns for the change columns to hold historic data.

For each source row without a matching primary key in the target, the Expression transformation marks the row new. For each source row with a matching primary key in the target, the Expression compares user-defined source and target columns. If those columns do not match, the Expression marks the row changed. The Update Strategy transformation, UPD_EMPLOYEE_TARGET, passes only the new rows to the target.

You can create the following transformations using the Incremental load templates wizard: