Trait transact::database::DatabaseReader

pub trait DatabaseReader {
    fn get(&self, key: &[u8]) -> Result<Option<Vec<u8>>, DatabaseError>;
    fn index_get(
        &self, 
        index: &str, 
        key: &[u8]
    ) -> Result<Option<Vec<u8>>, DatabaseError>;
    fn cursor(&self) -> Result<DatabaseCursor<'_>, DatabaseError>;
    fn index_cursor(
        &self, 
        index: &str
    ) -> Result<DatabaseCursor<'_>, DatabaseError>;
    fn count(&self) -> Result<usize, DatabaseError>;
    fn index_count(&self, index: &str) -> Result<usize, DatabaseError>;
}

A DatabaseReader provides read access to a database instance.

Required methods

fn get(&self, key: &[u8]) -> Result<Option<Vec<u8>>, DatabaseError>

Returns the bytes stored at the given key, if found.

fn index_get(
    &self,
    index: &str,
    key: &[u8]
) -> Result<Option<Vec<u8>>, DatabaseError>

Returns the bytes stored at the given key on a specified index, if found.

fn cursor(&self) -> Result<DatabaseCursor<'_>, DatabaseError>

Returns a cursor against the main database. The cursor iterates over the entries in the natural key order.

fn index_cursor(&self, index: &str) -> Result<DatabaseCursor<'_>, DatabaseError>

Returns a cursor against the given index. The cursor iterates over the entries in the index’s natural key order.

fn count(&self) -> Result<usize, DatabaseError>

Returns the number of entries in the main database.

fn index_count(&self, index: &str) -> Result<usize, DatabaseError>

Returns the number of entries in the given index.

Implementors

impl<'a> DatabaseReader for BTreeReader<'a>

impl<'a> DatabaseReader for BTreeWriter<'a>

impl<'a> DatabaseReader for LmdbDatabaseReader<'a>

impl<'a> DatabaseReader for LmdbDatabaseWriter<'a>