如何弃用特定类型类实例？

Question

我正在尝试执行以下操作，但在编译此源代码时不断遇到解析错误：

instance FromRow Job where
  {-# DEPRECATED fromRow "Please do not depend on the FromRow instance of the Job type. It does not handle optional features, such as job-results and job-workflows. Depending upon your scenario, use 'jobRowParserSimple' or 'jobRowParserWithWorkflow' directly." #-}
  fromRow = jobRowParserSimple

Haskell 可以做到这一点吗？怎么办？

Answer 1

{-# LANGUAGE OverloadedStrings #-}

import Database.PostgreSQL.Simple
import Database.PostgreSQL.Simple.FromRow

-- Define your Job type
data Job = Job { jobId :: Int, jobName :: String } deriving Show

-- Implement the FromRow instance
instance FromRow Job where
  fromRow = Job <$> field <*> field

main :: IO ()
main = do
  conn <- connectPostgreSQL "your_database_connection_string"

  -- Replace the SQL query with your actual query to fetch Job records
  jobs <- query_ conn "SELECT job_id, job_name FROM jobs" :: IO [Job]

  mapM_ print jobs

  close conn