Trait diesel::connection::Connection
[−]
[src]
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
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>,
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>,
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
.