db = DAL("sqlite://storage.sqlite")

db.define_table('highways',
                Field('lognum', unique=True),
                Field('route'),
                Field('direction'),
                Field('startdate'),
                format = '%(route)s')

db.highways.lognum.requires = IS_NOT_IN_DB(db, db.highways.lognum)
db.highways.lognum.requires = IS_NOT_EMPTY()