What are the core objects in the Salesforce Field Service data model?

The FSL data model centers on:

1. Work Order — the top-level service request, linked to an Account, Contact, and optionally an Asset or Case.
2. Work Order Line Item — individual tasks or steps within a Work Order.
3. Service Appointment — a scheduled visit linked to a Work Order or Line Item with start/end times.
4. Assigned Resource — junction object linking a Service Appointment to a Service Resource.
5. Service Resource — the technician, crew, or equipment performing work.
6. Service Territory — a geographic area.
7. Service Territory Member — links a resource to a territory with a role (primary or relocation).
8. Operating Hours — define business hours for territories and resources.
9. Time Sheet / Time Sheet Entry — track actual labor hours against service appointments.