{-# LANGUAGE OverloadedStrings, DataKinds #-} import Database.Cassandra.CQL import Control.Monad import Control.Monad.CatchIO import Control.Monad.Trans (liftIO) import Data.Int import Data.ByteString.Char8 (ByteString) import qualified Data.ByteString.Char8 as C import Data.Set (Set) import qualified Data.Set as S import Data.Text (Text) import qualified Data.Text as T import Data.UUID import System.Random dropLists :: Query Schema () () dropLists = "drop table sets" createLists :: Query Schema () () createLists = "create table sets (id uuid PRIMARY KEY, items set)" insert :: Query Write (UUID, Set Text) () insert = "insert into sets (id, items) values (?, ?)" select :: Query Rows () (Set Text) select = "select items from sets" 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 pool <- newPool [("localhost", "9042")] "test" -- servers, keyspace runCas pool $ do ignoreDropFailure $ liftIO . print =<< executeSchema QUORUM dropLists () liftIO . print =<< executeSchema QUORUM createLists () u1 <- liftIO randomIO u2 <- liftIO randomIO u3 <- liftIO randomIO executeWrite QUORUM insert (u1, S.fromList ["one", "two"]) executeWrite QUORUM insert (u2, S.fromList ["hundred", "two hundred"]) executeWrite QUORUM insert (u3, S.fromList ["dozen"]) liftIO . print =<< executeRows QUORUM select ()