Struct libmdbx::Cursor

source ·

pub struct Cursor<'txn, K>where
    K: TransactionKind,
{ /* private fields */ }

Expand description

A cursor for navigating the items within a table.

Implementations§

source §

impl<'txn, K> Cursor<'txn, K>
where K: TransactionKind,

source

pub fn cursor(&self) -> CursorPtr

Returns a raw pointer to the underlying MDBX cursor.

The caller must ensure that the pointer is not used after the lifetime of the cursor.

source

pub fn first<Key, Value>(&mut self) -> Result<Option<(Key, Value)>>
where Key: Decodable<'txn>, Value: Decodable<'txn>,

Position at first key/data item.

source

pub fn first_dup<Value>(&mut self) -> Result<Option<Value>>
where Value: Decodable<'txn>,

TableFlags::DUP_SORT-only: Position at first data item of current key.

source

pub fn get_both<Value>(&mut self, k: &[u8], v: &[u8]) -> Result<Option<Value>>
where Value: Decodable<'txn>,

TableFlags::DUP_SORT-only: Position at key/data pair.

source

pub fn get_both_range<Value>( &mut self, k: &[u8], v: &[u8] ) -> Result<Option<Value>>
where Value: Decodable<'txn>,

TableFlags::DUP_SORT-only: Position at given key and at first data greater than or equal to specified data.

source

pub fn get_current<Key, Value>(&mut self) -> Result<Option<(Key, Value)>>
where Key: Decodable<'txn>, Value: Decodable<'txn>,

Return key/data at current cursor position.

source

pub fn get_multiple<Value>(&mut self) -> Result<Option<Value>>
where Value: Decodable<'txn>,

DupFixed-only: Return up to a page of duplicate data items from current cursor position. Move cursor to prepare for Self::next_multiple().

source

pub fn last<Key, Value>(&mut self) -> Result<Option<(Key, Value)>>
where Key: Decodable<'txn>, Value: Decodable<'txn>,

Position at last key/data item.

source

pub fn last_dup<Value>(&mut self) -> Result<Option<Value>>
where Value: Decodable<'txn>,

DupSort-only: Position at last data item of current key.

source

pub fn next<Key, Value>(&mut self) -> Result<Option<(Key, Value)>>
where Key: Decodable<'txn>, Value: Decodable<'txn>,

Position at next data item

source

pub fn next_dup<Key, Value>(&mut self) -> Result<Option<(Key, Value)>>
where Key: Decodable<'txn>, Value: Decodable<'txn>,

TableFlags::DUP_SORT-only: Position at next data item of current key.

source

pub fn next_multiple<Key, Value>(&mut self) -> Result<Option<(Key, Value)>>
where Key: Decodable<'txn>, Value: Decodable<'txn>,

TableFlags::DUP_FIXED-only: Return up to a page of duplicate data items from next cursor position. Move cursor to prepare for MDBX_NEXT_MULTIPLE.

source

pub fn next_nodup<Key, Value>(&mut self) -> Result<Option<(Key, Value)>>
where Key: Decodable<'txn>, Value: Decodable<'txn>,

Position at first data item of next key.

source

pub fn prev<Key, Value>(&mut self) -> Result<Option<(Key, Value)>>
where Key: Decodable<'txn>, Value: Decodable<'txn>,

Position at previous data item.

source

pub fn prev_dup<Key, Value>(&mut self) -> Result<Option<(Key, Value)>>
where Key: Decodable<'txn>, Value: Decodable<'txn>,

TableFlags::DUP_SORT-only: Position at previous data item of current key.

source

pub fn prev_nodup<Key, Value>(&mut self) -> Result<Option<(Key, Value)>>
where Key: Decodable<'txn>, Value: Decodable<'txn>,

Position at last data item of previous key.

source

pub fn set<Value>(&mut self, key: &[u8]) -> Result<Option<Value>>
where Value: Decodable<'txn>,

Position at specified key.

source

pub fn set_key<Key, Value>( &mut self, key: &[u8] ) -> Result<Option<(Key, Value)>>
where Key: Decodable<'txn>, Value: Decodable<'txn>,

Position at specified key, return both key and data.

source

pub fn set_range<Key, Value>( &mut self, key: &[u8] ) -> Result<Option<(Key, Value)>>
where Key: Decodable<'txn>, Value: Decodable<'txn>,

Position at first key greater than or equal to specified key.

source

pub fn prev_multiple<Key, Value>(&mut self) -> Result<Option<(Key, Value)>>
where Key: Decodable<'txn>, Value: Decodable<'txn>,

TableFlags::DUP_FIXED-only: Position at previous page and return up to a page of duplicate data items.

source

pub fn set_lowerbound<Key, Value>( &mut self, key: &[u8], value: Option<&[u8]> ) -> Result<Option<(bool, Key, Value)>>
where Key: Decodable<'txn>, Value: Decodable<'txn>,

Position at first key-value pair greater than or equal to specified, return both key and data, and the return code depends on a exact match.

For non DupSort-ed collections this works the same as Self::set_range(), but returns false if key found exactly and true if greater key was found.

For DupSort-ed a data value is taken into account for duplicates, i.e. for a pairs/tuples of a key and an each data value of duplicates. Returns false if key-value pair found exactly and true if the next pair was returned.

source

pub fn iter<Key, Value>(&mut self) -> Iter<'txn, '_, K, Key, Value> ⓘ
where Self: Sized, Key: Decodable<'txn>, Value: Decodable<'txn>,

Iterate over table items. The iterator will begin with item next after the cursor, and continue until the end of the table. For new cursors, the iterator will begin with the first item in the table.