Trait diesel::connection::Connection

pub trait Connection: SimpleConnection + Sized + Send {
    type Backend: Backend;
    fn establish(database_url: &str) -> ConnectionResult<Self>;

    fn transaction<T, E, F>(&self, f: F) -> Result<T, E>
    where
        F: FnOnce() -> Result<T, E>,
        E: From<Error>,
    { ... }
    fn begin_test_transaction(&self) -> QueryResult<()> { ... }
    fn test_transaction<T, E, F>(&self, f: F) -> T
    where
        F: FnOnce() -> Result<T, E>,
    { ... }
}

Perform connections to a backend.

Associated Types

type Backend: Backend

The backend this connection represents.

Required Methods

fn establish(database_url: &str) -> ConnectionResult<Self>

Establishes a new connection to the database at the given URL. The URL should be a valid connection string for a given backend. See the documentation for the specific backend for specifics.

Provided Methods

fn transaction<T, E, F>(&self, f: F) -> Result<T, E> where
    F: FnOnce() -> Result<T, E>,
    E: From<Error>, 

Executes the given function inside of a database transaction. When a transaction is already occurring, savepoints will be used to emulate a nested transaction.

The error returned from the function must implement From<diesel::result::Error>.

fn begin_test_transaction(&self) -> QueryResult<()>

Creates a transaction that will never be committed. This is useful for tests. Panics if called while inside of a transaction.

fn test_transaction<T, E, F>(&self, f: F) -> T where
    F: FnOnce() -> Result<T, E>, 

Executes the given function inside a transaction, but does not commit it. Panics if the given function returns an Err.

Implementors