Printing records to PDF — Line items come from your relations

The line-items block walks the same link as subitems: a Relation field on the child table pointing back at this record. Point an invoice at its line items, or a job at its visits, and the rows appear in the order they were created. Values print the way they read in the app — a Relation shows the customer's name rather than an id, and a Rollup shows its computed total — so a PDF never leaks the plumbing underneath.