'Remove linked hrm_experience record
@param row: the link to be deleted
@param tablename: the tablename (ignored)'

@staticmethod
def deploy_assignment_experience_ondelete_cascade(row, tablename=None):

    s3db = current.s3db
    table = s3db.deploy_assignment_experience
    link = current.db((table.id == row.id)).select(table.id, table.experience_id, limitby=(0, 1)).first()
    if (not link):
        return
    else:
        link.update_record(experience_id=None)
    s3db.resource('hrm_experience', id=link.experience_id).delete()
