Table.hs

{-# language DeriveFunctor #-}
{-# language DerivingStrategies #-}
{-# language DisambiguateRecordFields #-}
{-# language NamedFieldPuns #-}
{-# language StandaloneKindSignatures #-}

module Rel8.Schema.Table
  ( TableSchema(..)
  , ppTable
  )
where

-- base
import Data.Kind ( Type )
import Prelude

-- opaleye
import qualified Opaleye.Internal.HaskellDB.Sql as Opaleye
import qualified Opaleye.Internal.HaskellDB.Sql.Print as Opaleye

-- pretty
import Text.PrettyPrint ( Doc )


-- | The schema for a table. This is used to specify the name and schema that a
-- table belongs to (the @FROM@ part of a SQL query), along with the schema of
-- the columns within this table.
-- 
-- For each selectable table in your database, you should provide a
-- @TableSchema@ in order to interact with the table via Rel8.
type TableSchema :: Type -> Type
data TableSchema names = TableSchema
  { name :: String
    -- ^ The name of the table.
  , schema :: Maybe String
    -- ^ The schema that this table belongs to. If 'Nothing', whatever is on
    -- the connection's @search_path@ will be used.
  , columns :: names
    -- ^ The columns of the table. Typically you would use a a higher-kinded
    -- data type here, parameterized by the 'Rel8.ColumnSchema.ColumnSchema' functor.
  }
  deriving stock Functor


ppTable :: TableSchema a -> Doc
ppTable TableSchema {name, schema} = Opaleye.ppTable Opaleye.SqlTable
  { sqlTableSchemaName = schema
  , sqlTableName = name
  }