Editing Transformations

If a previously added transformation is no longer working as it should, or, if the transformation parameters need to be updated, you can edit the transformation in the Data canvas.

Tip: By following the steps below, you can add transformations to an existing transformation group. You can also add more transformations anywhere in the data table structure, by selecting a node in the source view and clicking on the plus sign in the step list shown under the nodes. See To add transformations to a specific node in the source view for more information.

To edit a transformation:

1. On the authoring bar, click Data canvas .

2. Make sure the data table of interest is selected.

   Comment: This step is only applicable if you have two or more data tables in the analysis.

3. In the graphical structure, click on the node where the transformation to edit was added.

Comment: If there is an error in a transformation you will be guided to the affected node and transformation group by error icons.

Response: Details about the selected node are shown in the lower left part of the data canvas.

4. For the transformation group of interest, click the settings icon, .

   Comment: A transformation group is a section in the list of operations in the source view, containing one or more transformations. For example, the example below shows a transformation group with two transformations:
   

   Response: The Transform data dialog is opened.

5. In the Transform data dialog, click to select the transformation to update.

   Comment: Note that, in some cases, errors may be resolved for all transformations in a transformation group by editing the first transformation in a group, by removing a broken transformation, or, by changing the order of the transformations in the list.

6. Click Edit.

   Response: The transformation dialog for the selected transformation is opened. See Transforming Data for links to all available transformation dialogs.

7. When you are done with your changes, click OK.

   Comment: Note that if your changes affect any consecutive transformations, you may need to edit those transformations as well, to provide a valid result. If a succeeding transformation is broken, this will be indicated in the Transform data dialog or on another node in the data canvas.

8. Repeat steps 6-7 if you want to edit more transformations in the transformation group, or click OK to close the dialog.

Example: Broken transformation due to renamed columns in source

If you have added a transformation that uses a column from a linked source, and the column in the source is renamed, then the transformation will become broken in your analysis.

In this example, data has been loaded from a text file. Then, two transformations were inserted: first a "Calculate and replace column"-operation and then a "Change data types"-operation.

However, after a reload of the data, the column that was used in these transformations is no longer available because someone renamed the column in the linked text file source.

The error is indicated by an information icon or an exclamation mark on the node of interest in the data canvas:

By clicking on the affected node, you can show details about all operations done on the node, and the error icon guides you to the broken transformations.

Click on the settings icon, , to open the Transform data dialog:

Select the transformation you want to modify and click Edit.

In the transformation dialog, update the expression to use the new name instead of the missing column name:

Click OK when you are done with your changes.

When you have updated the transformations to use the new column name, all errors will be gone and the analysis is up to date again.