Question

因此,我计划与Sqlite使用0.9.0.1,我正在通过辅导:。

添加和盘问的简单幻灯没有汇编成册:

-- START
{-# LANGUAGE QuasiQuotes, TypeFamilies, GeneralizedNewtypeDeriving, TemplateHaskell,
             OverloadedStrings, GADTs, FlexibleContexts #-}
import Database.Persist
import Database.Persist.TH
import Database.Persist.Sqlite
import Control.Monad.IO.Class (liftIO)

share [mkPersist sqlSettings, mkSave "entityDefs"] [persist|
Person
    name String
    age Int
|]

main = withSqliteConn ":memory:" $ runSqlConn $ do
    runMigration $ migrate entityDefs (undefined :: Person) -- this line added: that s it!
    michaelId <- insert $ Person "Michael" 26
    michael <- get michaelId
    liftIO $ print michael
-- STOP

假设间谍活动显示没有承诺的<代码>Eq,Show,供生成者使用,奇怪:

data PersonGeneric (backend :: (* -> *) -> * -> *)
    = Person {personName :: String, personAge :: Int}
type Person =
    PersonGeneric Database.Persist.GenericSql.Raw.SqlPersist

我喜欢这样做:

    liftIO $ putStrLn $ "name: " ++ (personName $ fromJust michael) ++ ", age: " ++ (show $ personAge $ fromJust michael)

而后加起来则未能从Sqlite获得主要钥匙:

Migrating: CREATE TABLE "person"("id" INTEGER PRIMARY KEY,"name" VARCHAR NOT NULL,"age" INTEGER NOT NULL)
proto: Pattern match failure in do expression at Database/Persist/GenericSql.hs:109:25-45

任何想法? 是否与Sqlite持续合作?

Answer 1

从0.8版改为0.9版,我们不再包括<编码>Eq和show例。在<代码>后添加以下线:

deriving Show Eq

这本书仍然以原第0.10版为对象,但我试图在今后几天更新。

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