Opaleye.ToFields

Documentation

toFields :: Default ToFields haskells fields => haskells -> fields

toFields provides a convenient typeclass wrapper around the Field_ creation functions in Opaleye.SqlTypes. Besides convenience it doesn't provide any additional functionality.

It can be used with functions like runInsert to insert custom Haskell types into the database. The following is an example of a function for inserting custom types.

  customInsert
     :: ( Default ToFields haskells fields )
     => Connection
     -> Table fields fields'
     -> haskells
     -> IO Int64
  customInsert conn table haskells = runInsert conn table $ toFields haskells

In order to use this function with your custom types, you need to define an instance of Default ToFields for your custom types.

type ToFields = Constant

toFieldsExplicit :: ToFields haskells fields -> haskells -> fields