Database.Persist.Monad.Internal.SqlTransaction

Documentation

newtype SqlTransaction m a

The monad that tracks transaction state.

Conceptually equivalent to SqlPersistT, but restricts IO operations, for two reasons:

1. Forking a thread that uses the same SqlBackend as the current thread causes Bad Things to happen.
2. Transactions may need to be retried, in which case IO operations in a transaction are required to be rerunnable.

You shouldn't need to explicitly use this type; your functions should only declare the MonadSqlQuery constraint.

Constructors

UnsafeSqlTransaction

Fields

• unSqlTransaction :: ReaderT SqlTransactionEnv m a

Instances

MonadRerunnableTrans SqlTransaction

Defined in Database.Persist.Monad.Internal.SqlTransaction

Methods

rerunnableLift :: Monad m => m a -> SqlTransaction m a

MonadFix m => MonadFix (SqlTransaction m)

Defined in Database.Persist.Monad.Internal.SqlTransaction

Methods

mfix :: (a -> SqlTransaction m a) -> SqlTransaction m a

(TypeError ('Text "Cannot run arbitrary IO actions within a transaction. If the IO action is rerunnable, use rerunnableIO") :: Constraint, Monad m) => MonadIO (SqlTransaction m)

Defined in Database.Persist.Monad.Internal.SqlTransaction

Methods

liftIO :: IO a -> SqlTransaction m a

Applicative m => Applicative (SqlTransaction m)

Defined in Database.Persist.Monad.Internal.SqlTransaction

Methods

pure :: a -> SqlTransaction m a

(<*>) :: SqlTransaction m (a -> b) -> SqlTransaction m a -> SqlTransaction m b

liftA2 :: (a -> b -> c) -> SqlTransaction m a -> SqlTransaction m b -> SqlTransaction m c

(*>) :: SqlTransaction m a -> SqlTransaction m b -> SqlTransaction m b

(<*) :: SqlTransaction m a -> SqlTransaction m b -> SqlTransaction m a

Functor m => Functor (SqlTransaction m)

Defined in Database.Persist.Monad.Internal.SqlTransaction

Methods

fmap :: (a -> b) -> SqlTransaction m a -> SqlTransaction m b

(<$) :: a -> SqlTransaction m b -> SqlTransaction m a

Monad m => Monad (SqlTransaction m)

Defined in Database.Persist.Monad.Internal.SqlTransaction

Methods

(>>=) :: SqlTransaction m a -> (a -> SqlTransaction m b) -> SqlTransaction m b

(>>) :: SqlTransaction m a -> SqlTransaction m b -> SqlTransaction m b

return :: a -> SqlTransaction m a

MonadRerunnableIO m => MonadRerunnableIO (SqlTransaction m)

Defined in Database.Persist.Monad.Internal.SqlTransaction

Methods

rerunnableIO :: IO a -> SqlTransaction m a

(MonadSqlQuery m, MonadUnliftIO m) => MonadSqlQuery (SqlTransaction m)

Defined in Database.Persist.Monad.Internal.SqlTransaction

Associated Types

type TransactionM (SqlTransaction m) :: Type -> Type

Methods

runQueryRep :: Typeable record => SqlQueryRep record a -> SqlTransaction m a

withTransaction :: TransactionM (SqlTransaction m) a -> SqlTransaction m a

type TransactionM (SqlTransaction m)

Defined in Database.Persist.Monad.Internal.SqlTransaction

type TransactionM (SqlTransaction m) = TransactionM m

data SqlTransactionEnv

Constructors

SqlTransactionEnv

Fields

• sqlBackend :: SqlBackend
• ignoreCatch :: SomeException -> Bool

runSqlTransaction :: MonadUnliftIO m => SqlTransactionEnv -> SqlTransaction m a -> m a

catchSqlTransaction :: (MonadUnliftIO m, Exception e) => SqlTransaction m a -> (e -> SqlTransaction m a) -> SqlTransaction m a

Like normal catch, except ignores errors specified by ignoreCatch.