I'm working on a project at the moment and the client requires the import/export of customer records to/from their CRM. I've imported a fair few successfully however I've found something else that I might need help with.
The client said that they regularly change the email address assigned to customer records, so we will need to import those changes, however as far as I know, the only unique identifier for customer imports is the email address (there's no 'customer_id' or 'entity_id' columns present in the customer main file CSV export). As such, if the client were to change an email address and we imported an updated customer list, new customer will be created instead of updating the email address of existing ones.
Is there anything that I could use to overcome this issue? If we could import by the Customer ID, that would solve all issues, but as far as I'm aware, core Magento doesn't allow this?
Many thanks, Joe