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I've been trying to come up with a simple and intuitive way to use databases with Haskell. I've taken this code from the Yesod book and tried to clean it up so that it can be easier to understand and use. {-# LANGUAGE QuasiQuotes, TemplateHaskell, TypeFamilies, OverloadedStrings #-} {-# LANGUAGE GADTs, FlexibleContexts #-} import Database.Persist import Database.Persist.Sqlite (withSqliteConn, runSqlConn, runMigration) import Database.Persist.TH (share, mkPersist, mkMigrate, sqlSettings, persist) share [mkPersist sqlSettings, mkMigrate "migrateAll"] [persist| Person -- Table name name String -- String value age Int Maybe -- Numerical value |] updateDB x y = withSqliteConn "data.db" $ runSqlConn $ do runMigration migrateAll -- Creates "Person" table if one doesn't exist insert $ Person x $ Just y -- Inserts values into .db file main = do updateDB "Frank Silver" 40 -- adds name "Frank Silver" and age "40" to data.db file This code almost works, but I get the following error which I haven't been able to resolve. No instance for (Control.Monad.Trans.Resource.MonadResource IO) arising from a use of `updateDB' Possible fix: add an instance declaration for (Control.Monad.Trans.Resource.MonadResource IO) In a stmt of a 'do' block: updateDB "Frank Silver" 40 In the expression: do { updateDB "Frank Silver" 40 } In an equation for `main': main = do { updateDB "Frank Silver" 40 } Any suggestions pointing me in the right direction would be appreciated.

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