from gluon.contrib,appconfig import AppConfig

fram aluan.tonls import Auth

$$

configuration $=$ AppConfig$($reload$=$True$)$

if not request.env,web$2$py$\_$runtime$\_$gae:

# if NOT running on Google App Engine use SQLite or other DB

db $=$ DAL$("$mysql:$//$root: rootalocalhost$/$test$?$set$\_$encoding$=$utf$8$mb$4",$

migrate$\_$enabled$=$False$)$

else:

#${?}^{}{?}^x$

# connect to Google BigTable $($optional 'google:datastore:$//$namespace$\text{'})$

#

$db=$ DAL$(\text{'}$google:datastore $+ndb\text{'})$

# store sessions and tickets there

#

session. connect $($ request, response, $db=db)$

#

# or store session in Memcache, Redis, etc.

# from gluon, contrib. fiemdb import MEMDB

# from google.appengine.api. memcache import client

# session.connect $($request$,$ response, $db=$ MEMDB$($Client $()))$

#

db$.$define$\_$table$(\text{'}$authors$\text{'},$

Field$(\text{'}$id$\text{'},$ 'integer'$),$

Field$(\text{'}$name$\text{'},$ requires$=$IS$\_$NOT$\_$EMPTY$()),$

Field$(\text{'}$bio$\text{'},$ 'text'$),$

Field$(\text{'}$email$\text{'},$ requires$=$IS$\_$EMAIL$()),$

db$.$ define$\_$table$(\text{'}$books$\text{'},$

Field'$(\text{'}$id$\text{'},$ 'integer'$),$

Field$(\text{'}$titie$\text{'},$ requires$=$IS$\_$NOT$\_$EMPTY$()),$

Field$(\text{'}$author$\text{'},$ 'reference authors'$),$

'requires$=$IS$\_$INT$\_$IN$\_$RANGE $(1000,3000),$

What would happeb if you tried to insert a book with no author?