Now that we have defined the entities and the rules for how they will map to each other, we need to define how we will uniquely identify every record that we are synchronizing.
An example can explain why we need to do this. Let's say that we have customer information that is stored in both CRM and ERP, and that we are synchronizing the customer information between the two applications:
When the data changes in the ERP side, we need to synchronize the data with CRM and update the ERP side. One of the customer names is "Joe Bloggs and Sons' Bike Store".
If Joe Bloggs changes the name of his company to "Joe Bloggs ...