When you use a Sequence Generator transformation to replace missing keys, you can also use a Router transformation to filter null values from columns that have values assigned. You connect the Router transformation to the Sequence Generator transformation, and use NEXTVAL to generate a sequence of numeric values to populate the null values.

For example, to replace null values in a CUSTOMER_NO column, you create a mapping with a source that contains customer data. You add a Router transformation to filter customers with customer numbers assigned from those with null values. You add a Sequence Generator transformation to generate unique CUSTOMER_NO values. You add customer targets to write the data to.

The following image shows a mapping that replaces null values in the CUSTOMER_NO column: