persistBackend package:persistent-mtl

persistBackend :: HasPersistBackend backend => backend -> BaseBackend backend
persistent-mtl Database.Persist.Sql.Shim
class () => HasPersistBackend backend
persistent-mtl Database.Persist.Sql.Shim
Class which allows the plucking of a BaseBackend backend from some larger type. For example, instance HasPersistBackend (SqlReadBackend, Int) where type BaseBackend (SqlReadBackend, Int) = SqlBackend persistBackend = unSqlReadBackend . fst
class HasPersistBackend backend => IsPersistBackend backend
persistent-mtl Database.Persist.Sql.Shim
Class which witnesses that backend is essentially the same as BaseBackend backend. That is, they're isomorphic and backend is just some wrapper over BaseBackend backend.