Trait TransactionManager

pub trait TransactionManager<Conn: Connection> {
    type TransactionStateData;

    // Required methods
    fn begin_transaction(conn: &mut Conn) -> QueryResult<()>;
    fn rollback_transaction(conn: &mut Conn) -> QueryResult<()>;
    fn commit_transaction(conn: &mut Conn) -> QueryResult<()>;
    fn transaction_manager_status_mut(
        conn: &mut Conn,
    ) -> &mut TransactionManagerStatus;

    // Provided methods
    fn transaction<F, R, E>(conn: &mut Conn, callback: F) -> Result<R, E>
       where F: FnOnce(&mut Conn) -> Result<R, E>,
             E: From<Error> { ... }
    fn is_broken_transaction_manager(conn: &mut Conn) -> bool { ... }
}

Manages the internal transaction state for a connection.

You will not need to interact with this trait, unless you are writing an implementation of Connection.

Required Associated Types

type TransactionStateData

Data stored as part of the connection implementation to track the current transaction state of a connection

Required Methods

fn begin_transaction(conn: &mut Conn) -> QueryResult<()>

Begin a new transaction or savepoint

If the transaction depth is greater than 0, this should create a savepoint instead. This function is expected to increment the transaction depth by 1.

fn rollback_transaction(conn: &mut Conn) -> QueryResult<()>

Rollback the inner-most transaction or savepoint

If the transaction depth is greater than 1, this should rollback to the most recent savepoint. This function is expected to decrement the transaction depth by 1.

fn commit_transaction(conn: &mut Conn) -> QueryResult<()>

Commit the inner-most transaction or savepoint

If the transaction depth is greater than 1, this should release the most recent savepoint. This function is expected to decrement the transaction depth by 1.

fn transaction_manager_status_mut( conn: &mut Conn, ) -> &mut TransactionManagerStatus

Available on crate feature i-implement-a-third-party-backend-and-opt-into-breaking-changes only.

Fetch the current transaction status as mutable

Used to ensure that begin_test_transaction is not called when already inside of a transaction, and that operations are not run in a InError transaction manager.

Provided Methods

fn transaction<F, R, E>(conn: &mut Conn, callback: F) -> Result<R, E>

where F: FnOnce(&mut Conn) -> Result<R, E>, E: From<Error>,

Executes the given function inside of a database transaction

Each implementation of this function needs to fulfill the documented behaviour of Connection::transaction

fn is_broken_transaction_manager(conn: &mut Conn) -> bool

Available on crate feature i-implement-a-third-party-backend-and-opt-into-breaking-changes only.

This methods checks if the connection manager is considered to be broken by connection pool implementations

A connection manager is considered to be broken by default if it either contains an open transaction (because you don’t want to have connections with open transactions in your pool) or when the transaction manager is in an error state.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<Conn> TransactionManager<Conn> for AnsiTransactionManager

where Conn: Connection<TransactionManager = Self>,

type TransactionStateData = AnsiTransactionManager