Yesod Book :: Persistent :: One To One Relations

persistRelationOneToOne.hs

{-# LANGUAGE QuasiQuotes, TypeFamilies, GeneralizedNewtypeDeriving, TemplateHaskell,
             OverloadedStrings, GADTs, FlexibleContexts #-}
import Data.Conduit (runResourceT)
import Database.Persist
import Database.Persist.Sqlite
import Database.Persist.TH
import Control.Monad.IO.Class (liftIO)
import Control.Monad.Logger (runStderrLoggingT)
import Data.Time

share [mkPersist sqlSettings, mkMigrate "migrateAll"] [persistLowerCase|
Person
    name String
    deriving Show
Car
    ownerId PersonId Eq
    name String
    deriving Show
|]

main = runStderrLoggingT $ runResourceT $ withSqliteConn ":memory:" $ runSqlConn $ do
    runMigration migrateAll
    bruce <- insert $ Person "Bruce Wayne"
    insert $ Car bruce "Bat Mobile"
    insert $ Car bruce "Porsche"
    -- this could go on a while
    cars <- selectList [CarOwnerId ==. bruce] []
    liftIO $ print cars