Function deleteRefRecords

core/record_model.go:1581–1621

deleteRefRecords checks if related records has to be deleted (if `CascadeDelete` is set) OR just unset the record id from any relation field values (if they are not required). NB! This method is expected to be called from inside of a transaction.

(app App, mainRecord *Record, refRecords []*Record, field Field)

//
// NB! This method is expected to be called from inside of a transaction.
func deleteRefRecords(app App, mainRecord *Record, refRecords []*Record, field Field) error {
	relField, _ := field.(*RelationField)
	if relField == nil {
		return errors.New("only RelationField is supported at the moment, got " + field.Type())
	}

	for _, refRecord := range refRecords {
		ids := refRecord.GetStringSlice(relField.Name)

		// unset the record id
		for i := len(ids) - 1; i >= 0; i-- {
			if ids[i] == mainRecord.Id {
				ids = append(ids[:i], ids[i+1:]...)
				break
			}
		}

		// cascade delete the reference
		// (only if there are no other active references in case of multiple select)
		if relField.CascadeDelete && len(ids) == 0 {
			if err := app.Delete(refRecord); err != nil {
				return err
			}
			// no further actions are needed (the reference is deleted)
			continue
		}

		if relField.Required && len(ids) == 0 {
			return fmt.Errorf("the record cannot be deleted because it is part of a required reference in record %s (%s collection)", refRecord.Id, refRecord.Collection().Name)
		}

		// save the reference changes
		// (without validation because it is possible that another relation field to have a reference to a previous deleted record)
		refRecord.Set(relField.Name, ids)
		if err := app.SaveNoValidate(refRecord); err != nil {
			return err
		}
	}

	return nil
}