My tables all have keys.
Main table has a primary key
Subform 1 has the main table PK as a FK
Subform 2 has subform 1 PK as a FK, in addition to main table PK as a FK for reference
That is because each Inspection has many Samples, and each Sample can have many Errors. But I also want to keep track of which Inspection the Errors occurred on. Or is that already implied by the Inspections-Samples relationship? I didn't draw an Inspections-Errors relationship here due to previous comments about circular references.
Is that correct? Full relationship view – the 3 tables in the center are main form, subform 1, and subform 2: