Safe Haskell	Safe-Inferred
Language	GHC2021

Database.Persist.Sql.Lifted.Core

Synopsis

class (MonadSqlBackend db, MonadUnliftIO m) => MonadSqlTx db m | m -> db where
- runSqlTx :: HasCallStack => db a -> m a
class HasSqlBackend a where
- getSqlBackend :: a -> SqlBackend
data SqlBackend
class MonadUnliftIO m => MonadSqlBackend m where
- getSqlBackendM :: m SqlBackend
liftSql :: (MonadSqlBackend m, HasCallStack) => ReaderT SqlBackend m a -> m a

Documentation

class (MonadSqlBackend db, MonadUnliftIO m) => MonadSqlTx db m | m -> db where Source #

The constraint MonadSqlTx db m indicates that m is a monadic context that can run db actions, usually as a SQL transaction. Typically, this means that db needs a connection and m can provide one, e.g. from a connection pool.

Methods

runSqlTx :: HasCallStack => db a -> m a Source #

Runs the action in a SQL transaction

class HasSqlBackend a where Source #

Methods

getSqlBackend :: a -> SqlBackend Source #

Instances

Instances details

HasSqlBackend SqlBackend Source #
Instance details Defined in Database.Persist.Sql.Lifted.HasSqlBackend Methods getSqlBackend :: SqlBackend -> SqlBackend Source #

data SqlBackend #

A SqlBackend represents a handle or connection to a database. It contains functions and values that allow databases to have more optimized implementations, as well as references that benefit performance and sharing.

Instead of using the SqlBackend constructor directly, use the mkSqlBackend function.

A SqlBackend is *not* thread-safe. You should not assume that a SqlBackend can be shared among threads and run concurrent queries. This *will* result in problems. Instead, you should create a Pool SqlBackend, known as a ConnectionPool, and pass that around in multi-threaded applications.

To run actions in the persistent library, you should use the runSqlConn function. If you're using a multithreaded application, use the runSqlPool function.

Instances

Instances details

HasPersistBackend SqlBackend
Instance details Defined in Database.Persist.SqlBackend.Internal Associated Types type BaseBackend SqlBackend # Methods persistBackend :: SqlBackend -> BaseBackend SqlBackend #
IsPersistBackend SqlBackend
Instance details Defined in Database.Persist.SqlBackend.Internal Methods mkPersistBackend :: BaseBackend SqlBackend -> SqlBackend #
HasSqlBackend SqlBackend Source #
Instance details Defined in Database.Persist.Sql.Lifted.HasSqlBackend Methods getSqlBackend :: SqlBackend -> SqlBackend Source #
newtype BackendKey SqlBackend
Instance details Defined in Database.Persist.Sql.Orphan.PersistStore newtype BackendKey SqlBackend = SqlBackendKey { unSqlBackendKey :: Int64 }
type BaseBackend SqlBackend
Instance details Defined in Database.Persist.SqlBackend.Internal type BaseBackend SqlBackend = SqlBackend
type Rep (BackendKey SqlBackend)
Instance details Defined in Database.Persist.Sql.Orphan.PersistStore type Rep (BackendKey SqlBackend) = D1 ('MetaData "BackendKey" "Database.Persist.Sql.Orphan.PersistStore" "persistent-2.14.6.3-3LMJ8m0b8WSACag1tizLHI" 'True) (C1 ('MetaCons "SqlBackendKey" 'PrefixI 'True) (S1 ('MetaSel ('Just "unSqlBackendKey") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Int64)))

class MonadUnliftIO m => MonadSqlBackend m where Source #

A monadic context in which a SQL backend is available for running database queries

Methods

getSqlBackendM :: m SqlBackend Source #

Instances

Instances details

(HasSqlBackend r, MonadUnliftIO m) => MonadSqlBackend (ReaderT r m) Source #
Instance details Defined in Database.Persist.Sql.Lifted.MonadSqlBackend Methods getSqlBackendM :: ReaderT r m SqlBackend Source #

liftSql :: (MonadSqlBackend m, HasCallStack) => ReaderT SqlBackend m a -> m a Source #

Generalize from SqlPersistT to MonadSqlBackend