Database.PostgreSQL.PQTypes.Cursor

Documentation

newtype CursorName sql

Name of a cursor.

Constructors

CursorName

Fields

• unCursorName :: sql

Instances

IsString sql => IsString (CursorName sql)

Defined in Database.PostgreSQL.PQTypes.Cursor

Methods

fromString :: String -> CursorName sql

Show sql => Show (CursorName sql)

Defined in Database.PostgreSQL.PQTypes.Cursor

Methods

showsPrec :: Int -> CursorName sql -> ShowS

show :: CursorName sql -> String

showList :: [CursorName sql] -> ShowS

Eq sql => Eq (CursorName sql)

Defined in Database.PostgreSQL.PQTypes.Cursor

Methods

(==) :: CursorName sql -> CursorName sql -> Bool

(/=) :: CursorName sql -> CursorName sql -> Bool

Ord sql => Ord (CursorName sql)

Defined in Database.PostgreSQL.PQTypes.Cursor

Methods

compare :: CursorName sql -> CursorName sql -> Ordering

(<) :: CursorName sql -> CursorName sql -> Bool

(<=) :: CursorName sql -> CursorName sql -> Bool

(>) :: CursorName sql -> CursorName sql -> Bool

(>=) :: CursorName sql -> CursorName sql -> Bool

max :: CursorName sql -> CursorName sql -> CursorName sql

min :: CursorName sql -> CursorName sql -> CursorName sql

data Scroll

Defines whether a cursor will be declared as SCROLL or NO SCROLL. Scrollable cursors can be scrolled in all directions, otherwise only forward.

Constructors

Scroll

NoScroll

Instances

Show Scroll

Defined in Database.PostgreSQL.PQTypes.Cursor

Methods

showsPrec :: Int -> Scroll -> ShowS

show :: Scroll -> String

showList :: [Scroll] -> ShowS

Eq Scroll

Defined in Database.PostgreSQL.PQTypes.Cursor

Methods

(==) :: Scroll -> Scroll -> Bool

(/=) :: Scroll -> Scroll -> Bool

Ord Scroll

Defined in Database.PostgreSQL.PQTypes.Cursor

Methods

compare :: Scroll -> Scroll -> Ordering

(<) :: Scroll -> Scroll -> Bool

(<=) :: Scroll -> Scroll -> Bool

(>) :: Scroll -> Scroll -> Bool

(>=) :: Scroll -> Scroll -> Bool

max :: Scroll -> Scroll -> Scroll

min :: Scroll -> Scroll -> Scroll

data Hold

Defines whether a cursor will be declared as WITH HOLD or WITHOUT HOLD.

From the PostgreSQL manual: WITH HOLD specifies that the cursor can continue to be used after the transaction that created it successfully commits. WITHOUT HOLD specifies that the cursor cannot be used outside of the transaction that created it.

Constructors

Hold

NoHold

Instances

Show Hold

Defined in Database.PostgreSQL.PQTypes.Cursor

Methods

showsPrec :: Int -> Hold -> ShowS

show :: Hold -> String

showList :: [Hold] -> ShowS

Eq Hold

Defined in Database.PostgreSQL.PQTypes.Cursor

Methods

(==) :: Hold -> Hold -> Bool

(/=) :: Hold -> Hold -> Bool

Ord Hold

Defined in Database.PostgreSQL.PQTypes.Cursor

Methods

compare :: Hold -> Hold -> Ordering

(<) :: Hold -> Hold -> Bool

(<=) :: Hold -> Hold -> Bool

(>) :: Hold -> Hold -> Bool

(>=) :: Hold -> Hold -> Bool

max :: Hold -> Hold -> Hold

min :: Hold -> Hold -> Hold

data Cursor sql

Data representing a created cursor.

Instances

Show sql => Show (Cursor sql)

Defined in Database.PostgreSQL.PQTypes.Cursor

Methods

showsPrec :: Int -> Cursor sql -> ShowS

show :: Cursor sql -> String

showList :: [Cursor sql] -> ShowS

Eq sql => Eq (Cursor sql)

Defined in Database.PostgreSQL.PQTypes.Cursor

Methods

(==) :: Cursor sql -> Cursor sql -> Bool

(/=) :: Cursor sql -> Cursor sql -> Bool

Ord sql => Ord (Cursor sql)

Defined in Database.PostgreSQL.PQTypes.Cursor

Methods

compare :: Cursor sql -> Cursor sql -> Ordering

(<) :: Cursor sql -> Cursor sql -> Bool

(<=) :: Cursor sql -> Cursor sql -> Bool

(>) :: Cursor sql -> Cursor sql -> Bool

(>=) :: Cursor sql -> Cursor sql -> Bool

max :: Cursor sql -> Cursor sql -> Cursor sql

min :: Cursor sql -> Cursor sql -> Cursor sql

data CursorDirection

Direction in which to move the cursor. Note that cursors declared as NO SCROLL can only move forward (i.e. only CD_Next, CD_Forward_All and CD_Forward is allowed).

Constructors

CD_Next

CD_Prior

CD_First

CD_Last

CD_Forward_All

CD_Backward_All

CD_Absolute Int

CD_Relative Int

CD_Forward Int

CD_Backward Int

Instances

Show CursorDirection

Defined in Database.PostgreSQL.PQTypes.Cursor

Methods

showsPrec :: Int -> CursorDirection -> ShowS

show :: CursorDirection -> String

showList :: [CursorDirection] -> ShowS

Eq CursorDirection

Defined in Database.PostgreSQL.PQTypes.Cursor

Methods

(==) :: CursorDirection -> CursorDirection -> Bool

(/=) :: CursorDirection -> CursorDirection -> Bool

Ord CursorDirection

Defined in Database.PostgreSQL.PQTypes.Cursor

Methods

compare :: CursorDirection -> CursorDirection -> Ordering

(<) :: CursorDirection -> CursorDirection -> Bool

(<=) :: CursorDirection -> CursorDirection -> Bool

(>) :: CursorDirection -> CursorDirection -> Bool

(>=) :: CursorDirection -> CursorDirection -> Bool

max :: CursorDirection -> CursorDirection -> CursorDirection

min :: CursorDirection -> CursorDirection -> CursorDirection

cursorName :: Cursor sql -> CursorName sql

Retrieve the name of a cursor.

cursorQuery :: Cursor sql -> sql

Retrieve SQL query used to create a cursor.

withCursor :: (IsString sql, IsSQL sql, Monoid sql, MonadDB m, MonadMask m) => CursorName sql -> Scroll -> Hold -> sql -> (Cursor sql -> m r) -> m r

Create a cursor from the SQL query and use it within the given context.

withCursorSQL :: (MonadDB m, MonadMask m) => CursorName SQL -> Scroll -> Hold -> SQL -> (Cursor SQL -> m r) -> m r

Version of withCursor without the sql type parameter for convenience.

cursorFetch :: (IsSQL sql, IsString sql, Monoid sql, MonadDB m) => Cursor sql -> CursorDirection -> m Int

Retrieve rows from a query using a cursor. See https://www.postgresql.org/docs/current/sql-fetch.html for more information.

cursorFetch_ :: (IsSQL sql, IsString sql, Monoid sql, MonadDB m) => Cursor sql -> CursorDirection -> m ()

Same as cursorFetch, except the result (i.e. the number of fetched rows) is ignored.

cursorMove :: (IsSQL sql, IsString sql, Monoid sql, MonadDB m) => Cursor sql -> CursorDirection -> m Int

Move a cursor to a specific position. It works exactly like cursorFetch, except it only positions the cursor and does not return rows. See https://www.postgresql.org/docs/current/sql-move.html for more information.

cursorMove_ :: (IsSQL sql, IsString sql, Monoid sql, MonadDB m) => Cursor sql -> CursorDirection -> m ()

Same as cursorMove, except the result (i.e. the number of rows that would be fetched) is ignored.