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IT練習ノート

IT関連で調べたこと(実際は嵌ったこと)を書いています。

HaskellでMySQLにアクセス

サンドボックスの作成

(root)foo:mysqlsample foo$ cabal sandbox init
Writing a default package environment file to
/Users/foo/work03/haskelldatabase/mysqlsample/cabal.sandbox.config
Creating a new sandbox at
/Users/foo/work03/haskelldatabase/mysqlsample/.cabal-sandbox

ライブラリのインストール

(root)foo:mysqlsample foo$ cabal install HDBC-mysql 
Warning: The package list for 'hackage.haskell.org' is 22 days old.
Run 'cabal update' to get the latest list of available packages.
Resolving dependencies...
Notice: installing into a sandbox located at
/Users/foo/work03/haskelldatabase/mysqlsample/.cabal-sandbox
Configuring old-locale-1.0.0.7...
Configuring mtl-2.2.1...
Configuring utf8-string-1.0.1.1...
Configuring text-1.2.2.1...
Building utf8-string-1.0.1.1...
Building old-locale-1.0.0.7...
Building mtl-2.2.1...
Building text-1.2.2.1...
Installed old-locale-1.0.0.7
Configuring old-time-1.1.0.3...
Building old-time-1.1.0.3...
Installed mtl-2.2.1
Installed utf8-string-1.0.1.1
Installed old-time-1.1.0.3
Installed text-1.2.2.1
Configuring convertible-1.1.1.0...
Building convertible-1.1.1.0...
Installed convertible-1.1.1.0
Configuring HDBC-2.4.0.1...
Building HDBC-2.4.0.1...
Installed HDBC-2.4.0.1
Downloading HDBC-mysql-0.7.1.0...
Configuring HDBC-mysql-0.7.1.0...
Building HDBC-mysql-0.7.1.0...
Installed HDBC-mysql-0.7.1.0
Updating documentation index
/Users/foo/work03/haskelldatabase/mysqlsample/.cabal-sandbox/share/doc/x86_64-osx-ghc-8.0.1/index.html

インポート

(root)foo:mysqlsample foo$ cabal repl
GHCi, version 8.0.1: http://www.haskell.org/ghc/  :? for help
Prelude> import Database.HDBC 
Prelude Database.HDBC> import Database.HDBC.MySQL

コネクション取得

Prelude Database.HDBC Database.HDBC.MySQL> connectMySQL defaultMySQLConnectInfo {mysqlUser = "redmine", mysqlPassword = "my_password", mysqlDatabase="redmine"}
Prelude Database.HDBC Database.HDBC.MySQL> let con = connectMySQL defaultMySQLConnectInfo {mysqlUser = "redmine", mysqlPassword = "my_password", mysqlDatabase="redmine"}
Prelude Database.HDBC Database.HDBC.MySQL> :t con
con :: IO Connection

select実行

Prelude Database.HDBC Database.HDBC.MySQL> con >>= \x -> prepare x "select * from USERS" >>= (\y -> execute y [] >>= \_ -> fetchRow y)
Just [SqlInt32 1,SqlByteString "admin",SqlByteString "a99fe2fb647cb2a5e059e095c93d2ccc0588f76d",SqlByteString "Redmine",SqlByteString "Admin",SqlInt32 1,SqlInt32 1,SqlLocalTime 2015-02-01 20:33:33,SqlByteString "",SqlNull,SqlLocalTime 2015-12-07 20:51:38,SqlLocalTime 2015-12-07 21:39:45,SqlByteString "User",SqlNull,SqlByteString "all",SqlByteString "cb24cc9080698d1eb43f3c8b32189e4e",SqlInt32 0,SqlLocalTime 2015-12-07 21:39:45]