Is there a way to update a record in the AllSubscribers List from a Data Extension Import?
I'm hoping to set up a daily automation that imports data file into a Data Extension on the subscriber key that is not Email Address, but I'm worried if a subscriber changes their email address when it gets imported into the DE that it won't reflect in AllSubscribers.
Best Answer
It's certainly a recommendation to build an import process to your All Subscribers in order to keep in sync the email address from your Data Extension with the email address in All Subscribers.
Typically, if you import records to a data extension, those subscribers won't get added to 'All Subscribers' until you perform a send to the data extension / records.
When records do get added to 'All Subscribers' the email address is associated to their Subscriber Key (in your example, a key/guid)
A problem occurs when the customer changes their email address which is updated in your Data Extension, but when you then send an email again to the data extension / Subscriber Key, the email address on the All Subscribers record will be used (same issue if you have an implementation using Profile Attributes alongside Data Extensions of same field names)
If your import to the Data Extension is automated, then you can configure a second import step to import the same file to All Subscribers (do it as a separate step in your automation, else you will have contention on the file). Alternatively, you will want to perform a data extract of your data extension, transfer it to the FTP and then perform the import to All Subscribes. This will subsequently update the email address (and other Profile Attributes) for the Subscriber (Subscriber Key) in All Subscribers
From my early days with ExactTarget, I heard a rumour that there was back end rule/setting which Support could enable that allowed an email addresses for a Subscriber Key to be updated from a Send i.e. if the email address (and Profile Attributes) in the data extension differed from All Subscribers, then honour/update with the Data Extension values.
I'm not entirely sure if the rumour was true - and I've otherwise used the 'Email Address Changer' process described above and when I've raised the question with Support, this is always the direction I've been told to use.