Explains how to reuse repeated steps.
When you want to reuse a specific sequence of steps, you can turn the repetitive part into a mapping. A mapping is a standard transformation except that you can define mapping input and output steps as placeholders.
- Mapping Input Specification — the placeholder used for input from the parent transformation
- Mapping Output Specification — the placeholder from which the parent transformation reads data
Pentaho Data Integration samples that demonstrate the use of mapping steps are located at
Below is the reference for the Mapping (sub-transformation) step:
|Step name||Optionally, you can change the name of this step to fit your needs.|
|Mapping transformation||Specify the name of the mapping transformation file to execute at runtime. You can specify either a filename (XML/.ktr) or a transformation from the repository. The Edit button opens the specified transformation under a separate step in the Spoon Designer.|
|Parameters||Options under the Parameters tab allow you to define or pass PDI variables down to the mapping. This provides you with a high degree of customization.
It is possible to include variable expressions in the string values for the variable names.
Important! Only those variables/values that are specified are passed down to the sub-transformation.
|Input Tabs||Each of the Input tabs (may be missing) correspond to one Mapping Input Specification step in the mapping or sub-transformation. This means you can have multiple Input tabs in a single Mapping step. To add an Input tab, click Add Input.
|Output Tabs||Each of the Output tabs (may be missing) correspond to one Mapping Output Specification step in the mapping or sub-transformation. This means you can have multiple Output tabs in a single Mapping step. To add an Output tab, click Add Output.
|Add input / Add output||Add an input or output mapping for the specified sub-transformation|