What’s the best way to model following situation :
In some applications a customer is identified by a customer number. In some other applications the customer is identified by his social security number. So there are multiple type of business keys who identify the same customer. In some applications the link between the customer number and his social security number is available, but that’s not the case in all of our applications.
Should we create :
1) a hub for each type of business key ? Hub_Customer_Nbr and Hub_Customer_SSN with a link between those 2 Hubs
2) only one hub ? Hub_Customer which contains different types of business keys, so we have to add an extra field in the hub which indicates the type of BK ? And a SameAsLink to link the customer number to his SSN
3) other solution ?