Links between records

Real data is connected. An order belongs to a customer, a line item points at a product. Understudy turns those foreign keys into real links you can work with.

A reference is a link you can pick

A reference field holds the id of another record. In the editor it shows as a search-and-pick control: you search the target resource and choose a record, seeing a friendly label rather than a raw id.

• The stored value stays the plain id, so your responses still match the contract.
• Discovery wires references for you wherever it spots a belongs-to link, like order.customerId pointing at Customer.
• You can also add one by hand on any resource.

Derived values and inline expansion

A derived field copies a value from a linked record, like an order showing its customer's name. It is recomputed on every read, so it never drifts out of date.

And when your contract returns linked records inline, Understudy can expand them: return the customer object inside the order, not just the id. You get responses that look exactly like the real API's.