Change dimensions for target mapping

Hi KD. To your questions below, I believe the following is true:

1.In custom target mapping, is the email taken from the workflow temporary table?

A: The email itself is defined by the associated template. However, the personalization data, target, etc., need to be compiled with the temporary table created using a workflow. Whether the target mapping is custom or not, should not matter.

2.Is it necessary to use Change Dimension to Recipient before a recurring delivery when using custom target mapping? when to use change dimensions and when to not for target mapping?

A: I do not believe that it is always necessary to change the Dimension to Recipient if you are using a custom target mapping. That said, it would be entirely based on your implementation, so depending on your use case, there may be some dependency requiring such. As for when to use the Change Dimension activity, I would refer to the documentation below: https://experienceleague.adobe.com/en/docs/campaign-classic/using/automating-with-workflows/targeting-activities/change-dimension

3.We generally use Change Dimension to change the targeting dimension to Recipient before using Recurring Delivery. Is this related to Target Mapping, which is by default linked to the recipient table? Or is Recurring Delivery designed in a way that it only accepts Recipient as the targeting dimension?
A: I suspect that it's how your target mapping is configured, as I do believe Recurring deliveries are not restricted in which targeting mapping is used. If your target mapping has links to the recipient schema, it would make sense that your delivery would require the targeting dimension to be recipient prior to delivery.

Regards,

Craig