Learning Pentaho Data Integration 8 CE - Third Edition

Creating and executing sub-transformations

Sub-transformations are, as the name suggests, Transformations inside Transformations.

The PDI proper name for a sub-transformation is mapping. However, as the word mapping is also used with other meanings in PDI—an example of that is the mapping of table fields with stream fields in a Table output step—we will use the more intuitive name sub-transformation.

A common reason to create sub-transformations is to isolate functionality that is likely to be needed more than once, in a single Transformation or in different places of your project. You implement the functionality once, and then you use it any number of times by calling the sub-transformation with a single PDI step.

Sub-transformations are ...