Trait Cursor

pub trait Cursor<'txn> {
    // Required method
    fn cursor(&self) -> *mut MDB_cursor;

    // Provided methods
    fn get(
        &self,
        key: Option<&[u8]>,
        data: Option<&[u8]>,
        op: c_uint,
    ) -> Result<(Option<&'txn [u8]>, &'txn [u8])> { ... }
    fn iter(&mut self) -> Iter<'txn>  { ... }
    fn iter_start(&mut self) -> Iter<'txn>  { ... }
    fn iter_from<K>(&mut self, key: K) -> Iter<'txn> 
       where K: AsRef<[u8]> { ... }
    fn iter_dup(&mut self) -> IterDup<'txn>  { ... }
    fn iter_dup_start(&mut self) -> IterDup<'txn>  { ... }
    fn iter_dup_from<K>(&mut self, key: K) -> IterDup<'txn> 
       where K: AsRef<[u8]> { ... }
    fn iter_dup_of<K>(&mut self, key: K) -> Iter<'txn> 
       where K: AsRef<[u8]> { ... }
}

An LMDB cursor.

Required Methods

fn cursor(&self) -> *mut MDB_cursor

Returns a raw pointer to the underlying LMDB cursor.

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

Provided Methods

fn get( &self, key: Option<&[u8]>, data: Option<&[u8]>, op: c_uint, ) -> Result<(Option<&'txn [u8]>, &'txn [u8])>

Retrieves a key/data pair from the cursor. Depending on the cursor op, the current key may be returned.

fn iter(&mut self) -> Iter<'txn>

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

For databases with duplicate data items (DatabaseFlags::DUP_SORT), the duplicate data items of each key will be returned before moving on to the next key.

fn iter_start(&mut self) -> Iter<'txn>

Iterate over database items starting from the beginning of the database.

For databases with duplicate data items (DatabaseFlags::DUP_SORT), the duplicate data items of each key will be returned before moving on to the next key.

fn iter_from<K>(&mut self, key: K) -> Iter<'txn>

where K: AsRef<[u8]>,

Iterate over database items starting from the given key.

For databases with duplicate data items (DatabaseFlags::DUP_SORT), the duplicate data items of each key will be returned before moving on to the next key.

fn iter_dup(&mut self) -> IterDup<'txn>

Iterate over duplicate database items. The iterator will begin with the item next after the cursor, and continue until the end of the database. Each item will be returned as an iterator of its duplicates.

fn iter_dup_start(&mut self) -> IterDup<'txn>

Iterate over duplicate database items starting from the beginning of the database. Each item will be returned as an iterator of its duplicates.

fn iter_dup_from<K>(&mut self, key: K) -> IterDup<'txn>

where K: AsRef<[u8]>,

Iterate over duplicate items in the database starting from the given key. Each item will be returned as an iterator of its duplicates.

fn iter_dup_of<K>(&mut self, key: K) -> Iter<'txn>

where K: AsRef<[u8]>,

Iterate over the duplicates of the item in the database with the given key.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<'txn> Cursor<'txn> for RoCursor<'txn>

impl<'txn> Cursor<'txn> for RwCursor<'txn>