The holdingDays on a HoldingTimeViolation is the number Piper computed by subtracting collectionDate from analysisDate. Comparing holdingDays to limitDays shows exactly how bad the violation is: if holdingDays is 16 and limitDays is 14, the sample was held 2 days too long (overByDays = 2). This calculation is stored explicitly so that the violation record is self-contained and does not require recalculation when dates are reviewed later, even if underlying date fields are corrected.
Technical section
Data model, API, and internals — visible to developers.