Trait Database

pub trait Database:
    Send
    + Sync
    + Debug {
    type TX: DbTx + Send + Sync + Debug + 'static;
    type TXMut: DbTxMut + DbTx + TableImporter + Send + Sync + Debug + 'static;

    // Required methods
    fn tx(&self) -> Result<Self::TX, DatabaseError>;
    fn tx_mut(&self) -> Result<Self::TXMut, DatabaseError>;
    fn path(&self) -> PathBuf;
    fn oldest_reader_txnid(&self) -> Option<u64>;
    fn last_txnid(&self) -> Option<u64>;

    // Provided methods
    fn view<T, F>(&self, f: F) -> Result<T, DatabaseError>
       where F: FnOnce(&mut Self::TX) -> T { ... }
    fn update<T, F>(&self, f: F) -> Result<T, DatabaseError>
       where F: FnOnce(&Self::TXMut) -> T { ... }
}

Expand description

Main Database trait that can open read-only and read-write transactions.

Sealed trait which cannot be implemented by 3rd parties, exposed only for consumption.

Required Associated Types§

type TX: DbTx + Send + Sync + Debug + 'static

Read-Only database transaction

type TXMut: DbTxMut + DbTx + TableImporter + Send + Sync + Debug + 'static

Read-Write database transaction

Required Methods§

fn tx(&self) -> Result<Self::TX, DatabaseError>

Create read only transaction.

fn tx_mut(&self) -> Result<Self::TXMut, DatabaseError>

Create read write transaction only possible if database is open with write access.

fn path(&self) -> PathBuf

Returns the path to the database directory.

fn oldest_reader_txnid(&self) -> Option<u64>

Returns the transaction ID of the oldest active reader, if available.

This is the committed txnid of the snapshot the reader is pinned to, not a unique per-reader identifier, so multiple readers can report the same txnid.

Used to check whether stale readers from a previous write transaction have completed. Returns None if no readers are active or the backend does not support this query.