A mapplet is reusable transformation logic that you can use to transform source data before it is loaded into the target.
Create mapplets in Data Integration in the Mapplet Designer in the same way that you create mappings in the Mapping Designer. After you create a mapplet, you can add it to a Mapplet transformation to use its transformation logic. You can use any transformation in a mapplet.
You can use a mapplet in another mapplet. However, you cannot cyclically reference a mapplet. For example, if Mapplet A uses Mapplet B, Mapplet B cannot also use Mapplet A.
You can't use a mapplet in a mapping in SQL ELT mode.