I a have a file drop automation which is importing data into specific data extension - there is no subscriber info in the data and I do not want to set one to email address. What would be the best way to auto generate Subscriber Key?
I personally don't recommend SFMC providing Subscriber Key to your contacts. The only way you can identify/deduplicate your subscribers on import will still be on email address - which will change over time and generate duplicate records, and leading to inconsistent tracking history.
There is a number of methods to generate a unique identifier in SFMC, if you really insist on building this solution. I would use NewID() in a Query Activity you trigger in the context of your import, in following way:
- Import the file to a staging DE
- Lookup the email addresses that are not in your master contacts DE
- For these addresses, generate the NewID
- Add these records to your master contacts DE, with the newsy generated IDs being your Subscriber Key