deleted Data Extension still causing “duplicate key value” error for creating DE with same name

Question

Using the Python FuelSDK, I created a Data Extension. I then used the dashboard to delete it, and I saw it successfully delete.

Upon again creating a Data Extension with the same name, I received this error:
"Error occurred while saving Custom Object <My Data Extension Name> (00000000-0000-0000-0000-000000000000): Cannot insert duplicate key row in object 'dbo.CustomObject' with unique index 'IX_CustomObject_MemberID_CustomerKey_uncl'. The duplicate key value is (<Some Number>, <My Data Extension Name>)."

Is this perhaps because of Exacttarget still having the original Data Extension cached, and soon I will be able to again create a Data Extension with that name?

Or is this name in fact never usable again?

(Name and CustomerKey have the same value in this case, so I'm saying "name" in the above question but note that I'm also talking about "CustomerKey".)

Answer 1

When deleting the data extension, the Marketing Cloud will slightly modify the name and make the data extension "inactive" on the database. What it does NOT do, is modify the External (customer) Key. Since this must be a unique value across your account, you cannot reuse this External Key unless you also modify this prior to deleting it.

If you need to reuse this external key, you'll want to reach out to SFMC Support and request they rename this on the back-end.

Best practice will be to either rename this prior to deletion, or not define an external key upon creation so a random GUID is created, that would be unique each time.