Hasql.CursorTransaction

Types

data CursorTransaction s result

Context for fetching from multiple cursors in an intertwined fashion.

Instances

Monad (CursorTransaction s)

Methods

(>>=) :: CursorTransaction s a -> (a -> CursorTransaction s b) -> CursorTransaction s b

(>>) :: CursorTransaction s a -> CursorTransaction s b -> CursorTransaction s b

return :: a -> CursorTransaction s a

fail :: String -> CursorTransaction s a

Functor (CursorTransaction s)

Methods

fmap :: (a -> b) -> CursorTransaction s a -> CursorTransaction s b

(<$) :: a -> CursorTransaction s b -> CursorTransaction s a

Applicative (CursorTransaction s)

Methods

pure :: a -> CursorTransaction s a

(<*>) :: CursorTransaction s (a -> b) -> CursorTransaction s a -> CursorTransaction s b

(*>) :: CursorTransaction s a -> CursorTransaction s b -> CursorTransaction s b

(<*) :: CursorTransaction s a -> CursorTransaction s b -> CursorTransaction s a

data Cursor s

Cursor reference.

data BatchSize

Spefifies how many rows to fetch in a single DB roundtrip.

data EncodedParams

A parameters encoder immediately supplied with parameters.

Instances

Monoid EncodedParams

Methods

mempty :: EncodedParams

mappend :: EncodedParams -> EncodedParams -> EncodedParams

mconcat :: [EncodedParams] -> EncodedParams

Cursor Transactions

declareCursor :: ByteString -> EncodedParams -> CursorTransaction s (Cursor s)

Given a template and encoded params produces a cursor, while automating its resource management.

fetchBatch :: Cursor s -> BatchSize -> Result result -> CursorTransaction s result

Fetch from a cursor a batch of the given size and decode it using the specified result decoder.

transaction :: Transaction result -> CursorTransaction s result

Lift a standard transaction. Note that the transaction must not execute other CursorTransactions.

Batch Sizes

batchSize_10 :: BatchSize

Batch size of 10.

batchSize_100 :: BatchSize

Batch size of 100.

batchSize_1000 :: BatchSize

Batch size of 1000.

batchSize_10000 :: BatchSize

Batch size of 10000.

Encoded Params

encodedParams :: Params params -> params -> EncodedParams

Pack the params encoder and params into EncodedParams.