Trait redb::ReadableTable

pub trait ReadableTable<K: RedbKey + 'static, V: RedbValue + 'static>: Sealed {
    // Required methods
    fn get<'a>(
        &self,
        key: impl Borrow<K::SelfType<'a>>
    ) -> Result<Option<AccessGuard<'_, V>>, StorageError>
       where K: 'a;
    fn range<'a, KR>(
        &self,
        range: impl RangeBounds<KR> + 'a
    ) -> Result<Range<'_, K, V>, StorageError>
       where K: 'a,
             KR: Borrow<K::SelfType<'a>> + 'a;
    fn stats(&self) -> Result<TableStats, StorageError>;
    fn len(&self) -> Result<u64, StorageError>;
    fn is_empty(&self) -> Result<bool, StorageError>;

    // Provided methods
    fn first(
        &self
    ) -> Result<Option<(AccessGuard<'_, K>, AccessGuard<'_, V>)>, StorageError> { ... }
    fn last(
        &self
    ) -> Result<Option<(AccessGuard<'_, K>, AccessGuard<'_, V>)>, StorageError> { ... }
    fn iter(&self) -> Result<Range<'_, K, V>, StorageError> { ... }
}

Required Methods

fn get<'a>( &self, key: impl Borrow<K::SelfType<'a>> ) -> Result<Option<AccessGuard<'_, V>>, StorageError>

where K: 'a,

Returns the value corresponding to the given key

fn range<'a, KR>( &self, range: impl RangeBounds<KR> + 'a ) -> Result<Range<'_, K, V>, StorageError>

where K: 'a, KR: Borrow<K::SelfType<'a>> + 'a,

Returns a double-ended iterator over a range of elements in the table

Examples

Usage:

use redb::*;
const TABLE: TableDefinition<&str, u64> = TableDefinition::new("my_data");

let db = Database::create(filename)?;
let write_txn = db.begin_write()?;
{
    let mut table = write_txn.open_table(TABLE)?;
    table.insert("a", &0)?;
    table.insert("b", &1)?;
    table.insert("c", &2)?;
}
write_txn.commit()?;

let read_txn = db.begin_read()?;
let table = read_txn.open_table(TABLE)?;
let mut iter = table.range("a".."c")?;
let (key, value) = iter.next().unwrap()?;
assert_eq!("a", key.value());
assert_eq!(0, value.value());

fn stats(&self) -> Result<TableStats, StorageError>

Retrieves information about storage usage for the table

fn len(&self) -> Result<u64, StorageError>

Returns the number of entries in the table

fn is_empty(&self) -> Result<bool, StorageError>

Returns true if the table is empty

Provided Methods

fn first( &self ) -> Result<Option<(AccessGuard<'_, K>, AccessGuard<'_, V>)>, StorageError>

Returns the first key-value pair in the table, if it exists

fn last( &self ) -> Result<Option<(AccessGuard<'_, K>, AccessGuard<'_, V>)>, StorageError>

Returns the last key-value pair in the table, if it exists

fn iter(&self) -> Result<Range<'_, K, V>, StorageError>

Returns a double-ended iterator over all elements in the table

Object Safety

This trait is not object safe.

Implementors

impl<'db, 'txn, K: RedbKey + 'static, V: RedbValue + 'static> ReadableTable<K, V> for Table<'db, 'txn, K, V>

impl<'txn, K: RedbKey + 'static, V: RedbValue + 'static> ReadableTable<K, V> for ReadOnlyTable<'txn, K, V>