Trait tetsy_kvdb::KeyValueDB [−][src]
Generic key-value database.
The KeyValueDB
deals with "column families", which can be thought of as distinct
stores within a database. Keys written in one column family will not be accessible from
any other. The number of column families must be specified at initialization, with a
differing interface for each database.
The API laid out here, along with the Sync
bound implies interior synchronization for
implementation.
Required methods
fn get(&self, col: u32, key: &[u8]) -> Result<Option<DBValue>>
[src]
Get a value by key.
fn get_by_prefix(&self, col: u32, prefix: &[u8]) -> Option<Box<[u8]>>
[src]
Get the first value matching the given prefix.
fn write(&self, transaction: DBTransaction) -> Result<()>
[src]
Write a transaction of changes to the backing store.
fn iter<'a>(
&'a self,
col: u32
) -> Box<dyn Iterator<Item = (Box<[u8]>, Box<[u8]>)> + 'a>
[src]
&'a self,
col: u32
) -> Box<dyn Iterator<Item = (Box<[u8]>, Box<[u8]>)> + 'a>
Iterate over the data for a given column.
fn iter_with_prefix<'a>(
&'a self,
col: u32,
prefix: &'a [u8]
) -> Box<dyn Iterator<Item = (Box<[u8]>, Box<[u8]>)> + 'a>
[src]
&'a self,
col: u32,
prefix: &'a [u8]
) -> Box<dyn Iterator<Item = (Box<[u8]>, Box<[u8]>)> + 'a>
Iterate over the data for a given column, returning all key/value pairs where the key starts with the given prefix.
fn restore(&self, new_db: &str) -> Result<()>
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Attempt to replace this database with a new one located at the given path.
Provided methods
fn transaction(&self) -> DBTransaction
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Helper to create a new transaction.
fn io_stats(&self, _kind: IoStatsKind) -> IoStats
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Query statistics.
Not all tetsy-kvdb implementations are able or expected to implement this, so by default, empty statistics is returned. Also, not all tetsy-kvdb implementation can return every statistic or configured to do so (some statistics gathering may impede the performance and might be off by default).
fn has_key(&self, col: u32, key: &[u8]) -> Result<bool>
[src]
Check for the existence of a value by key.
fn has_prefix(&self, col: u32, prefix: &[u8]) -> bool
[src]
Check for the existence of a value by prefix.