sea-orm/src/database/connection.rs
2022-11-06 12:55:21 +08:00

68 lines
2.4 KiB
Rust

use crate::{
DatabaseTransaction, DbBackend, DbErr, ExecResult, QueryResult, Statement, TransactionError,
};
use futures::Stream;
use std::{future::Future, pin::Pin};
/// Creates constraints for any structure that can create a database connection
/// and execute SQL statements
#[async_trait::async_trait]
pub trait ConnectionTrait: Sync {
/// Fetch the database backend as specified in [DbBackend].
/// This depends on feature flags enabled.
fn get_database_backend(&self) -> DbBackend;
/// Execute a [Statement]
async fn execute(&self, stmt: Statement) -> Result<ExecResult, DbErr>;
/// Execute a [Statement] and return a query
async fn query_one(&self, stmt: Statement) -> Result<Option<QueryResult>, DbErr>;
/// Execute a [Statement] and return a collection Vec<[QueryResult]> on success
async fn query_all(&self, stmt: Statement) -> Result<Vec<QueryResult>, DbErr>;
/// Check if the connection supports `RETURNING` syntax on insert and update
fn support_returning(&self) -> bool {
let db_backend = self.get_database_backend();
db_backend.support_returning()
}
/// Check if the connection is a test connection for the Mock database
fn is_mock_connection(&self) -> bool {
false
}
}
/// Stream query results
pub trait StreamTrait: Send + Sync {
/// Create a stream for the [QueryResult]
type Stream<'a>: Stream<Item = Result<QueryResult, DbErr>> + Send
where
Self: 'a;
/// Execute a [Statement] and return a stream of results
fn stream<'a>(
&'a self,
stmt: Statement,
) -> Pin<Box<dyn Future<Output = Result<Self::Stream<'a>, DbErr>> + 'a + Send>>;
}
/// Spawn database transaction
#[async_trait::async_trait]
pub trait TransactionTrait {
/// Execute SQL `BEGIN` transaction.
/// Returns a Transaction that can be committed or rolled back
async fn begin(&self) -> Result<DatabaseTransaction, DbErr>;
/// Execute the function inside a transaction.
/// If the function returns an error, the transaction will be rolled back. If it does not return an error, the transaction will be committed.
async fn transaction<F, T, E>(&self, callback: F) -> Result<T, TransactionError<E>>
where
F: for<'c> FnOnce(
&'c DatabaseTransaction,
) -> Pin<Box<dyn Future<Output = Result<T, E>> + Send + 'c>>
+ Send,
T: Send,
E: std::error::Error + Send;
}