In the designer, navigate to Tools | Mapping Designer | Mapping | Wizard | Slowly Changing Dimensions, as shown in the following screenshot:

A new window will pop up, asking you the name (m_SCD1) of the new SCD mapping. Select Type 1 Dimension - keep most recent values in the target, as we are implementing SCD1. Click on Next as follows:

The next screen will ask you to select the source. Select a source from the dropdown. All the sources present in your repository will be listed in this drop-down list. We are using EMP_FILE.txt as the source file for our reference. Also, specify the name of the target you wish to create. We will name the target as EMPLOYEE_SCD1 in this book for our reference. Click on Next.

In the next window, select EMPLOYEE_ID as Logical Key Field. This specifies which column will be used to check for the existence of data in the target. Make sure that the column you use is the Key column of...