IsolationLevel.hs

module Database.Persist.SqlBackend.Internal.IsolationLevel where

import Data.String (IsString (..))

-- | Please refer to the documentation for the database in question for a full
-- overview of the semantics of the varying isolation levels
data IsolationLevel
    = ReadUncommitted
    | ReadCommitted
    | RepeatableRead
    | Serializable
    deriving (Show, Eq, Enum, Ord, Bounded)

makeIsolationLevelStatement :: (Monoid s, IsString s) => IsolationLevel -> s
makeIsolationLevelStatement l =
    "SET TRANSACTION ISOLATION LEVEL " <> case l of
        ReadUncommitted -> "READ UNCOMMITTED"
        ReadCommitted -> "READ COMMITTED"
        RepeatableRead -> "REPEATABLE READ"
        Serializable -> "SERIALIZABLE"