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GHC 9.14.1 · lts/ghc-9.14.x · 7a6c33e · 2026-10-12

Modulepostgresql-simple-0.7.0.1Haskell2010

Database.PostgreSQL.Simple.Cursor

Contents

Types
Cursor management
Folding over rows from a cursor

Synopsis

data Cursor
value declareCursor
value closeCursor
value foldForward
value foldForwardWithParser

Packagepostgresql-simple-0.7.0.1
Exports5
LanguageHaskell2010
LicenceBSD-3-Clause
SourceCursor.hs

Types

datadata Cursor

Cursor within a transaction.

Cursor management

valuedeclareCursor :: Connection -> Query -> IO Cursor

Declare a temporary cursor. The cursor is given a unique name for the given connection.

valuecloseCursor :: Cursor -> IO ()

Close the given cursor.

Folding over rows from a cursor

valuefoldForward

:: FromRow r
=> Cursor
-> Int
-> a -> r -> IO a
-> a
-> IO (Either a a)

Fold over a chunk of rows, calling the supplied fold-like function on each row as it is received. In case the cursor is exhausted, a Left value is returned, otherwise a Right value is returned.

valuefoldForwardWithParser

:: Cursor
-> RowParser r
-> Int
-> a -> r -> IO a
-> a
-> IO (Either a a)

Fold over a chunk of rows from the given cursor, calling the supplied fold-like function on each row as it is received. In case the cursor is exhausted, a Left value is returned, otherwise a Right value is returned.