Optional Nodes
Using optional nodes will produce a warning when you test your map. There are two conditions in which a source node may be considered optional:
The actual record or field is optional.
The source record or field is required, but a parent, grandparent, and farther up the hierarchy is optional.
You may have situations when you have records and fields in a source schema that are optional, but the destination schema requires the corresponding records or fields.
In both of the possible conditions, testing your map produces a warning in the Output window. In addition, the output data will not include the target node.