如何在Yesod应用程序中的GHCi中执行数据库查询 [英] How to perform database queries in GHCi in Yesod Application

问题描述

例如，如何使用Yesod应用程序的模型将新用户插入数据库？还是有更好的方法？

我正在处理脚手架应用程序。现在我创建了 App 实例，并且不知道如何使用它执行请求。

 ：额外
数据额外
 =额外{extraCopyright :: Data.Text.Internal.Text，
 extraAnalytics ::可能Data.Text.Internal.Text} 
  -  - 定义于`Settings 
 
 let e = ExtraasdfNothing 
 let c = AppConfig {appEnv = Development，appPort = 3000，appRoot =/，appHost =localhost， appExtra = e} 
f<  -  makeFoundation c 
：tf 
f :: App 
 
：i App 
 data App 
 = App { settings :: AppConfig DefaultEnv Extra，
 getStatic :: Yesod.Static.Static，
 connPool :: persistent-1.2.3.0：Database.Persist.Class.PersistConfig.PersistConfigPool 
 PersistConf，
 httpManager :: http-client-0.2.0.1：Network.HTTP.Client.Types.Manager，
 persistConfig :: PersistConf，
 appLogger :: Yesod.Core.Types.Logger} 
  - 定义于`Foundati '
  

下一步是什么？


解决方案

如果您只想在ghci中执行持久查询，则可以在不创建Yesod应用程序的情况下执行此操作。不幸的是，这样做有一点不同，具体取决于你想要使用的具体后端。

对于SQLite：

 > import Database.Persist.Sqlite 
>导入模型
> pool<  -  createSqlitePoolyesod-test.sqlite32 
> runSqliteyesod-test.sqlite3（runMigration migrateAll）
> userId<  -  runSqliteyesod-test.sqlite3（insert（[e-mail]））
  

对于Postgresql：

   - 在Shell中：$ createdb yesod-test 
> import Database.PostgreSQL.Simple 
> con<  -  connectPostgreSQLdbname = yesod-test
> import Database.Persist.Postgresql 
> pcon<  -  openSimpleConn con 
>导入模型
> runSqlPersistM（runMigration migrateAll）pcon 
> userId<  -  runSqlPersistM（insert（[e-mail]））pcon 
> Just user<  -  runSqlPersistM（get userId）pcon 
> userIdent用户
  

How to, for example, insert a new User into a database using Yesod application's models? Or is there a better way?

I am dealing with scaffolded application. Now I created App instance and dont know how to perform requests using it.

:i Extra
data Extra
  = Extra {extraCopyright :: Data.Text.Internal.Text,
           extraAnalytics :: Maybe Data.Text.Internal.Text}
        -- Defined in `Settings

let e = Extra "asdf" Nothing
let c = AppConfig {appEnv = Development, appPort = 3000, appRoot = "/", appHost = "localhost", appExtra = e}
f <- makeFoundation c
:t f
f :: App

:i App
data App
  = App {settings :: AppConfig DefaultEnv Extra,
         getStatic :: Yesod.Static.Static,
         connPool :: persistent-1.2.3.0:Database.Persist.Class.PersistConfig.PersistConfigPool
                       PersistConf,
         httpManager :: http-client-0.2.0.1:Network.HTTP.Client.Types.Manager,
         persistConfig :: PersistConf,
         appLogger :: Yesod.Core.Types.Logger}
        -- Defined in `Foundation'

What next?

解决方案

If you just want to do Persistent queries in ghci you can do this without creating a Yesod application. Unfortunately doing this is differs quite a bit depending on the specific back end you want to use.

For SQLite:

> import Database.Persist.Sqlite
> import Model
> pool <- createSqlitePool "yesod-test.sqlite3" 2
> runSqlite "yesod-test.sqlite3" (runMigration migrateAll)
> userId <- runSqlite "yesod-test.sqlite3" (insert (User "[e-mail]" Nothing))

For Postgresql:

-- In Shell: $ createdb yesod-test
> import Database.PostgreSQL.Simple
> con <- connectPostgreSQL  "dbname=yesod-test"
> import Database.Persist.Postgresql
> pcon <- openSimpleConn con
> import Model
> runSqlPersistM (runMigration migrateAll) pcon
> userId <- runSqlPersistM (insert (User "[e-mail]" Nothing)) pcon
> Just user <- runSqlPersistM (get userId) pcon
> userIdent user

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