# Parameters tab

![Mapping Parameters Tab](https://3411831820-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FAYwCj9fPr1B2pjC11IOQ%2Fuploads%2Fgit-blob-23f1e291f54e59c88861d6a5e95e6ea3a56b0e70%2FPDI_TransStep_Mapping_Parameters_Tab.png?alt=media)

You can use the following fields in the **Parameters** tab to define or pass Kettle variables down to the mapping sub-transformation.

| Option                                                   | Description                                                                                                                                                                                        |
| -------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Variable Name**                                        | Add a string you want to assign as a variable.                                                                                                                                                     |
| **String Value (can include variable expressions)**      | Add the value you want to assign to this variable name. It is possible to include variable expressions in the string values for the variable names.                                                |
| **Inherit all variables from the parent transformation** | Select this option to make all variables that are available in the parent transformation available in the sub-transformation, even if they are not explicitly specified in the **Parameters** tab. |

\*\*Note:\*\* When this option is not checked, only those variables/values that are specified are passed down to the sub-transformation.