Trait tetsy_kvdb_web::KeyValueDB[−][src]

pub trait KeyValueDB: Sync + Send + MallocSizeOf {
    fn get(
        &self, 
        col: u32, 
        key: &[u8]
    ) -> Result<Option<Vec<u8, Global>>, Error>;

    fn get_by_prefix(
        &self, 
        col: u32, 
        prefix: &[u8]
    ) -> Option<Box<[u8], Global>>;

    fn write(&self, transaction: DBTransaction) -> Result<(), Error>;

    fn iter(
        &'a self, 
        col: u32
    ) -> Box<dyn Iterator<Item = (Box<[u8], Global>, Box<[u8], Global>)> + 'a, Global>;

    fn iter_with_prefix(
        &'a self, 
        col: u32, 
        prefix: &'a [u8]
    ) -> Box<dyn Iterator<Item = (Box<[u8], Global>, Box<[u8], Global>)> + 'a, Global>;

    fn restore(&self, new_db: &str) -> Result<(), Error>;

    fn transaction(&self) -> DBTransaction { ... }

    fn io_stats(&self, _kind: Kind) -> IoStats { ... }

    fn has_key(&self, col: u32, key: &[u8]) -> Result<bool, Error> { ... }

    fn has_prefix(&self, col: u32, prefix: &[u8]) -> bool { ... }
}
Expand description

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

Get a value by key.

Get the first value matching the given prefix.

Write a transaction of changes to the backing store.

Iterate over the data for a given column.

Iterate over the data for a given column, returning all key/value pairs where the key starts with the given prefix.

Attempt to replace this database with a new one located at the given path.

Provided methods

Helper to create a new transaction.

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).

Check for the existence of a value by key.

Check for the existence of a value by prefix.

Implementations on Foreign Types

Implementors