Copyright	(c) Ole Krüger 2015-2016
License	BSD3
Maintainer	Ole Krüger <ole@vprsm.de>
Safe Haskell	None
Language	Haskell2010

Database.PostgreSQL.Store.Errand

Contents

Errand
Execute queries
Prepare statements
Transactions
Helpers

Description

Synopsis

Errand

data ErrandError Source #

Error during errand

Constructors

NoResult	No `Result` has been returned.
UserError String	A user has thrown an error.
ExecError ExecStatus ErrorCode ByteString ByteString ByteString	Query execution failed.
ParseError RowError	Result processing failed.

Instances

Eq ErrandError Source #
Methods (==) :: ErrandError -> ErrandError -> Bool # (/=) :: ErrandError -> ErrandError -> Bool #
Show ErrandError Source #
Methods showsPrec :: Int -> ErrandError -> ShowS # show :: ErrandError -> String # showList :: [ErrandError] -> ShowS #
Monoid ErrandError Source #
Methods mempty :: ErrandError # mappend :: ErrandError -> ErrandError -> ErrandError # mconcat :: [ErrandError] -> ErrandError #
MonadError ErrandError Errand Source #
Methods throwError :: ErrandError -> Errand a # catchError :: Errand a -> (ErrandError -> Errand a) -> Errand a #

data ErrorCode Source #

Error codes

Constructors

UnknownErrorCause ByteString
IntegrityViolation
RestrictViolation
NotNullViolation
ForeignKeyViolation
UniqueViolation
CheckViolation
ExclusionViolation

Instances

Eq ErrorCode Source #
Methods (==) :: ErrorCode -> ErrorCode -> Bool # (/=) :: ErrorCode -> ErrorCode -> Bool #
Show ErrorCode Source #
Methods showsPrec :: Int -> ErrorCode -> ShowS # show :: ErrorCode -> String # showList :: [ErrorCode] -> ShowS #

data Errand a Source #

An interaction with the database

Instances

Monad Errand Source #
Methods (>>=) :: Errand a -> (a -> Errand b) -> Errand b # (>>) :: Errand a -> Errand b -> Errand b # return :: a -> Errand a # fail :: String -> Errand a #
Functor Errand Source #
Methods fmap :: (a -> b) -> Errand a -> Errand b # (<$) :: a -> Errand b -> Errand a #
Applicative Errand Source #
Methods pure :: a -> Errand a # (<>) :: Errand (a -> b) -> Errand a -> Errand b # (>) :: Errand a -> Errand b -> Errand b # (<*) :: Errand a -> Errand b -> Errand a #
Alternative Errand Source #
Methods empty :: Errand a # (<\|>) :: Errand a -> Errand a -> Errand a # some :: Errand a -> Errand [a] # many :: Errand a -> Errand [a] #
MonadIO Errand Source #
Methods liftIO :: IO a -> Errand a #
MonadError ErrandError Errand Source #
Methods throwError :: ErrandError -> Errand a # catchError :: Errand a -> (ErrandError -> Errand a) -> Errand a #

runErrand :: Connection -> Errand a -> IO (Either ErrandError a) Source #

Run an errand.

Execute queries

execute :: ErrandQuery q Result => q r -> ErrandResult q Result Source #

Execute the query and return its internal result.

execute' :: ErrandQuery q Int => q r -> ErrandResult q Int Source #

Same as execute but instead of a Result it returns the number of affected rows.

query :: (Entity r, ErrandQuery q [r]) => q r -> ErrandResult q [r] Source #

Execute a query and process its result set.

queryWith :: (ErrandQuery q [r], KnownNat n) => RowParser n r -> q r -> ErrandResult q [r] Source #

Execute a query and process its result set using the provided RowParser.

Prepare statements

prepare :: PrepQuery a r -> Errand () Source #

Prepare a preparable query.

Transactions

beginTransaction :: Errand () Source #

Begin a transaction.

commitTransaction :: Errand () Source #

Commit transaction.

saveTransaction :: ByteString -> Errand () Source #

Create savepoint within transaction.

rollbackTransaction :: Errand () Source #

Roll back transaction.

rollbackTransactionTo :: ByteString -> Errand () Source #

Roll back to a specific savepoint.

withTransaction :: Errand a -> Errand () Source #

Do something within a transaction.

Helpers

class ErrandQuery q r where Source #

Identifies q as a query object.

Minimal complete definition

executeWith

Associated Types

type ErrandResult q r Source #

A type equal to Errand r or a function which will eventually yield a Errand r

Methods

executeWith :: (Result -> Errand r) -> q x -> ErrandResult q r Source #

Execute the query described in q x and pass its Result to the given function.

Instances

ErrandQuery Query r Source #
Associated Types type ErrandResult (Query :: * -> ) r :: Source # Methods executeWith :: (Result -> Errand r) -> Query x -> ErrandResult Query r Source #
ErrandQuery Statement r Source #
Associated Types type ErrandResult (Statement :: * -> ) r :: Source # Methods executeWith :: (Result -> Errand r) -> Statement x -> ErrandResult Statement r Source #
WithTuple ts => ErrandQuery (PrepQuery ts) r Source #
Associated Types type ErrandResult (PrepQuery ts :: * -> ) r :: Source # Methods executeWith :: (Result -> Errand r) -> PrepQuery ts x -> ErrandResult (PrepQuery ts) r Source #