{-# LANGUAGE OverloadedStrings, DataKinds #-} import Database.Cassandra.CQL import Control.Monad import Control.Monad.CatchIO import Control.Monad.Trans (liftIO) import Data.ByteString.Char8 (ByteString) import qualified Data.ByteString.Char8 as C import Data.Text (Text) import qualified Data.Text as T import Data.UUID import System.Random dropSongs :: Query Schema () () dropSongs = "drop table songs" createSongs :: Query Schema () () createSongs = "create table songs (id uuid PRIMARY KEY, title ascii, artist varchar, femaleSinger boolean, timesPlayed int, comment text)" insertSong :: Query Write (UUID, ByteString, Text, Bool, Int, Maybe Text) () insertSong = "insert into songs (id, title, artist, femaleSinger, timesPlayed, comment) values (?, ?, ?, ?, ?, ?)" getSongs :: Query Rows () (UUID, ByteString, Text, Bool, Int, Maybe Text) getSongs = "select id, title, artist, femaleSinger, timesPlayed, comment from songs" getOneSong :: Query Rows UUID (Text, Int) getOneSong = "select artist, timesPlayed from songs where id=?" ignoreDropFailure :: Cas () -> Cas () ignoreDropFailure code = code `catch` \exc -> case exc of ConfigError _ _ -> return () -- Ignore the error if the table doesn't exist _ -> throw exc main = do {- Assuming a 'test' keyspace already exists. Here's some CQL to create it: CREATE KEYSPACE test WITH replication = { 'class' : 'SimpleStrategy', 'replication_factor' : '1' }; -} pool <- newPool [("localhost", "9042")] "test" -- servers, keyspace runCas pool $ do ignoreDropFailure $ liftIO . print =<< executeSchema QUORUM dropSongs () liftIO . print =<< executeSchema QUORUM createSongs () u1 <- liftIO randomIO u2 <- liftIO randomIO u3 <- liftIO randomIO executeWrite QUORUM insertSong (u1, "La Grange", "ZZ Top", False, 2, Nothing) executeWrite QUORUM insertSong (u2, "Your Star", "Evanescence", True, 799, Nothing) executeWrite QUORUM insertSong (u3, "Angel of Death", "Slayer", False, 50, Just "Singer Tom Araya") songs <- executeRows QUORUM getSongs () liftIO $ forM_ songs $ \(uuid, title, artist, female, played, mComment) -> do putStrLn "" putStrLn $ "id : "++show uuid putStrLn $ "title : "++C.unpack title putStrLn $ "artist : "++T.unpack artist putStrLn $ "female singer : "++show female putStrLn $ "times played : "++show played putStrLn $ "comment : "++show mComment liftIO $ putStrLn "" liftIO . print =<< executeRow QUORUM getOneSong u2