A consultant should use an external object to access account order information from an ERP system. An external object is similar to a custom object, but the record data is stored outside the Salesforce organization.
By using external objects, the consultant can access the order data in real time via web service callouts, without replicating the data in Salesforce. This way, the sales teams can view the current state of the order information related to an account, without wasting storage and resources keeping data in sync1. A standard Order object or a custom object would require copying the order data from the ERP system to the Salesforce organization, which is not the desired solution for UC. References: 1: External Objects2