Does the Google Data API have the ability to merge two contacts based on their entry ids?
My place of employment allows multiple email addresses for the same person.
I'm writing an application to remove alias email addresses and merge duplicate contacts to prevent losing Calendar appointments. The application detects duplicate Contacts based on the person's internal LDAP uid, but the Google Data API doesn't appear to have the ability to merge Contacts based on two entry IDs unless I'm overlooking the contacts API documentation
This describes how to manually merge the contacts or use the Contact Manager to automate the merge process, but the automated merge process is based on the contact's name and not the contact's internal uid.
The Contacts API doesn't provide a built-in function to merge contacts, but your application could accomplish the same by copying over relevant fields and then deleting the extra contacts.
来源：https://stackoverflow.com/questions/26389180/google-data-api-merge-contacts