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1. data ParserErrorLevel

   persistent	Database.Persist.Quasi.PersistSettings

   No documentation available.

2. data ParserWarning

   persistent	Database.Persist.Quasi.PersistSettings

   No documentation available.

3. data PersistSettings

   persistent	Database.Persist.Quasi.PersistSettings

   No documentation available.

4. data ParserErrorLevel

   persistent	Database.Persist.Quasi.PersistSettings.Internal

   No documentation available.

5. data ParserWarning

   persistent	Database.Persist.Quasi.PersistSettings.Internal

   No documentation available.

6. ParserWarning :: String -> ParseError String Void -> PosState String -> ParserWarning

   persistent	Database.Persist.Quasi.PersistSettings.Internal

   No documentation available.

7. data PersistSettings

   persistent	Database.Persist.Quasi.PersistSettings.Internal

   No documentation available.

8. PersistSettings :: Text -> Text -> EntityNameHS -> ConstraintNameHS -> Text -> Bool -> Text -> Maybe ParserErrorLevel -> Maybe ParserErrorLevel -> PersistSettings

   persistent	Database.Persist.Quasi.PersistSettings.Internal

   No documentation available.

9. class PersistField a => PersistFieldSql a

   persistent	Database.Persist.Sql

   Tells Persistent what database column type should be used to store a Haskell type.

   Examples

   Simple Boolean Alternative

   data Switch = On | Off
   deriving (Show, Eq)
   
   instance PersistField Switch where
   toPersistValue s = case s of
   On -> PersistBool True
   Off -> PersistBool False
   fromPersistValue (PersistBool b) = if b then Right On else Right Off
   fromPersistValue x = Left $ "File.hs: When trying to deserialize a Switch: expected PersistBool, received: " <> T.pack (show x)
   
   instance PersistFieldSql Switch where
   sqlType _ = SqlBool
   

   Non-Standard Database Types

   If your database supports non-standard types, such as Postgres' uuid, you can use SqlOther to use them:

   import qualified Data.UUID as UUID
   instance PersistField UUID where
   toPersistValue = PersistLiteralEncoded . toASCIIBytes
   fromPersistValue (PersistLiteralEncoded uuid) =
   case fromASCIIBytes uuid of
   Nothing -> Left $ "Model/CustomTypes.hs: Failed to deserialize a UUID; received: " <> T.pack (show uuid)
   Just uuid' -> Right uuid'
   fromPersistValue x = Left $ "File.hs: When trying to deserialize a UUID: expected PersistLiteralEncoded, received: "-- >  <> T.pack (show x)
   
   instance PersistFieldSql UUID where
   sqlType _ = SqlOther "uuid"
   

   User Created Database Types

   Similarly, some databases support creating custom types, e.g. Postgres' DOMAIN and ENUM features. You can use SqlOther to specify a custom type:

   CREATE DOMAIN ssn AS text
   CHECK ( value ~ '^[0-9]{9}$');
   

   instance PersistFieldSQL SSN where
   sqlType _ = SqlOther "ssn"
   

   CREATE TYPE rainbow_color AS ENUM ('red', 'orange', 'yellow', 'green', 'blue', 'indigo', 'violet');
   

   instance PersistFieldSQL RainbowColor where
   sqlType _ = SqlOther "rainbow_color"
   

10. data PersistentSqlException

    persistent	Database.Persist.Sql

    No documentation available.

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