hasql 0.1.0 → 0.1.1

raw patch · 3 files changed

+129/−13 lines, 3 filesdep +hasqldep +hasql-postgresdep +transformersPVP ok

version bump matches the API change (PVP)

Dependencies added: hasql, hasql-postgres, transformers

API changes (from Hackage documentation)

Files

demo/Main.hs +67/−0
hasql.cabal +54/−10
library/Hasql.hs +8/−3

+ demo/Main.hs view

@@ -0,0 +1,67 @@+-- You can execute this file with 'cabal bench demo'.+{-# LANGUAGE QuasiQuotes, ScopedTypeVariables, OverloadedStrings #-}++import Control.Monad+import Control.Monad.IO.Class+import Control.Monad.Trans.Class+import Control.Monad.Trans.Maybe+import Data.Functor.Identity++-- Import the API from the "hasql" library+import qualified Hasql as H++-- Import the backend settings from the "hasql-postgres" library+import qualified Hasql.Postgres as H+++main = do++  let postgresSettings = H.Postgres "localhost" 5432 "postgres" "" "postgres"++  -- Prepare session settings with a smart constructor,+  -- which checks the inputted values on correctness.+  -- Set the connections pool size to 6 and the timeout to 30.+  sessionSettings <- maybe (fail "Improper session settings") return $ +                     H.sessionSettings 6 30++  -- Run a database session,+  -- while automatically managing the resources and exceptions.+  H.session postgresSettings sessionSettings $ do++    -- Execute a group of statements without any locking and ACID guarantees:+    H.tx Nothing $ do+      H.unit [H.q|DROP TABLE IF EXISTS a|]+      H.unit [H.q|CREATE TABLE a (id SERIAL NOT NULL, balance INT8, PRIMARY KEY (id))|]+      -- Insert three rows:+      replicateM_ 3 $ do +        H.unit [H.q|INSERT INTO a (balance) VALUES (0)|]++    -- Declare a list of transfer settings, which we'll later use.+    -- The tuple structure is: +    -- @(withdrawalAccountID, arrivalAccountID, amount)@+    let transfers :: [(Int, Int, Int)] = +          [(1, 2, 20), (2, 1, 30), (2, 3, 100)]++    forM_ transfers $ \(id1, id2, amount) -> do+      -- Run a transaction with ACID guarantees.+      -- Hasql will automatically roll it back and retry it in case of conflicts.+      H.tx (Just (H.Serializable, True)) $ do+        -- Use MaybeT to handle empty results:+        runMaybeT $ do+          do+            Identity balance1 <- MaybeT $ H.single $ [H.q|SELECT balance FROM a WHERE id=?|] id1+            Identity balance2 <- MaybeT $ H.single $ [H.q|SELECT balance FROM a WHERE id=?|] id2+            lift $ H.unit $ [H.q|UPDATE a SET balance=? WHERE id=?|] (balance1 - amount) id1+            lift $ H.unit $ [H.q|UPDATE a SET balance=? WHERE id=?|] (balance2 + amount) id2++    -- Output all the updated rows:+    do+      -- Unfortunately in this case there's no way to infer the type of the results,+      -- so we need to specify it explicitly:+      rows :: [(Int, Int)] <- H.tx Nothing $ H.list $ [H.q|SELECT * FROM a|]+      forM_ rows $ \(id, amount) -> do+        liftIO $ putStrLn $ "ID: " ++ show id ++ ", Amount: " ++ show amount++++

hasql.cabal view

@@ -1,31 +1,49 @@ name:   hasql version:-  0.1.0+  0.1.1 synopsis:   A minimalistic general high level API for relational databases description:   A robust and concise yet powerful API for communication with arbitrary-  relational databases. Features:+  relational databases.    .+  __Features__:+  .   * Concise and crisp API. Just a few functions and two monads doing all the   boilerplate job for you.   .+  * A powerful transaction abstraction, which provides +  an automated resolution of conflicts.+  The API ensures that you're only able to perform a specific+  set of actions in the transaction context,+  which allows Hasql to safely resolve conflicting transactions +  by automatically retrying them.+  This is much inspired by STM and ST.+  .+  * Support for cursors. Allows to fetch virtually limitless result sets in a+  constant memory using streaming.+  .+  * Employment of prepared statements. +  Every statement you emit gets prepared and cached. +  This raises the performance of the backend.+  .   * Automated management of resources related to connections, transactions and   cursors.   .   * A built-in connections pool.   .-  * Employment of prepared statements. Every statement you emit gets prepared-  and cached. This raises the performance of the backend.-  .-  * Support for cursors. Allows to fetch virtually limitless result sets in a-  constant memory using streaming.-  .   * Type-level generation of templates. You just can't write a statement with an   incorrect number of placeholders.   .   * Mapping to any types actually supported by the backend.+  .+  __Links__:+  .+  * <../src/demo/Main.hs A basic tutorial-demo>+  .+  * <http://hackage.haskell.org/package/hasql-postgres A PostgreSQL backend>+  . category:   Database homepage:@@ -58,6 +76,12 @@ library   hs-source-dirs:     library+  ghc-options:+    -funbox-strict-fields+  default-extensions:+    Arrows, BangPatterns, ConstraintKinds, DataKinds, DefaultSignatures, DeriveDataTypeable, DeriveFunctor, DeriveGeneric, EmptyDataDecls, FlexibleContexts, FlexibleInstances, FunctionalDependencies, GADTs, GeneralizedNewtypeDeriving, ImpredicativeTypes, LambdaCase, LiberalTypeSynonyms, MagicHash, MultiParamTypeClasses, MultiWayIf, NoImplicitPrelude, NoMonomorphismRestriction, OverloadedStrings, PatternGuards, ParallelListComp, QuasiQuotes, RankNTypes, RecordWildCards, ScopedTypeVariables, StandaloneDeriving, TemplateHaskell, TupleSections, TypeFamilies, TypeOperators, UnboxedTuples+  default-language:+    Haskell2010   other-modules:     Hasql.Prelude     Hasql.QQ@@ -93,9 +117,29 @@     mtl-prelude == 2.*,     base-prelude >= 0.1.3 && < 0.2,     base >= 4.5 && < 4.8+++-- Well, it's not a benchmark actually, +-- but there's no better way to specify an executable, +-- which is not intended for distribution, in Cabal.+benchmark demo+  type: +    exitcode-stdio-1.0+  hs-source-dirs:+    demo+  main-is:+    Main.hs   ghc-options:+    -O2+    -threaded+    "-with-rtsopts=-N"     -funbox-strict-fields-  default-extensions:-    Arrows, BangPatterns, ConstraintKinds, DataKinds, DefaultSignatures, DeriveDataTypeable, DeriveFunctor, DeriveGeneric, EmptyDataDecls, FlexibleContexts, FlexibleInstances, FunctionalDependencies, GADTs, GeneralizedNewtypeDeriving, ImpredicativeTypes, LambdaCase, LiberalTypeSynonyms, MagicHash, MultiParamTypeClasses, MultiWayIf, NoImplicitPrelude, NoMonomorphismRestriction, OverloadedStrings, PatternGuards, ParallelListComp, QuasiQuotes, RankNTypes, RecordWildCards, ScopedTypeVariables, StandaloneDeriving, TemplateHaskell, TupleSections, TypeFamilies, TypeOperators, UnboxedTuples   default-language:     Haskell2010+  build-depends:+    hasql-postgres == 0.1.*,+    hasql == 0.1.*,+    transformers,+    base >= 4.5 && < 4.8++

library/Hasql.hs view

@@ -1,3 +1,8 @@+-- |+-- This is the API of the \"hasql\" library.+-- For an introduction to the package +-- and links to more documentation please refer to +-- <index.html the package's index page>. module Hasql (   -- * Session@@ -8,9 +13,6 @@   SessionSettings,   sessionSettings, -  -- ** Error-  Error(..),-   -- * Transaction   Tx,   Mode,@@ -32,6 +34,9 @@    -- * Row parser   RowParser.RowParser(..),+  +  -- * Error+  Error(..), ) where