Hi, I was wondering about this situation and I found the answer in this post: https://nation.marketo.com/t5/Product-Discussions/Add-Field-to-Unique-Constraint/m-p/171236#M121709
but I also wanted to know if we were to change the unique constraint to be email AND first and last name, what would happen if the name fields were blank ? Would it input as null? would it input as empty string? or would it just outright fail to process?
In practice, when it comes to String fields on the Person/Lead in Marketo, there is no difference between null and the empty string. (This is not the case for Custom Object fields, where true null-ness can be differentiated from empty-ness.)
The lead will be considered to have empty LastName/FirstName and a form post will still be processed, not rejected.
I would be extremely wary of using a compound dedupe key, especially this one. It's a recipe for dirty data.
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