Disjoint data partitions

Data partitioning is disjoint when the remote databases do not share data. For example, each sales representative has their own set of customers and they do not share customers with other sales representatives.

In the following example, three tables store information about the interactions between sales representatives and customers: Customers, Contacts, and SalesReps. Each sales representative sells to several customers. For some customers, there is a single contact, and for other customers there are multiple contacts.

The Contacts table has a foreign key to the Customers table. The Customers table has a foreign key to the SalesReps table.
 Description of Contacts, Customers, and SalesReps tables

BEFORE UPDATE triggers