Trait ExprDataSource 

pub trait ExprDataSource<T = Value>: DataSource {
    // Required methods
    fn execute(
        &self,
        expr: &Expression<T>,
    ) -> impl Future<Output = Result<T, VantageError>> + Send;
    fn defer(&self, expr: Expression<T>) -> DeferredFn<T>
       where T: Clone + Send + Sync + 'static;

    // Provided method
    fn associate<R>(
        &self,
        expr: Expression<T>,
    ) -> AssociatedExpression<'_, Self, T, R>
       where Self: Sized { ... }
}

DataSource that can also execute expressions.

Required Methods

fn execute( &self, expr: &Expression<T>, ) -> impl Future<Output = Result<T, VantageError>> + Send

fn defer(&self, expr: Expression<T>) -> DeferredFn<T>

where T: Clone + Send + Sync + 'static,

Provided Methods

fn associate<R>( &self, expr: Expression<T>, ) -> AssociatedExpression<'_, Self, T, R>

where Self: Sized,

Create an associated expression with type-safe return type

Examples

let count_expr = expr!("SELECT COUNT(*) FROM users");
let associated = ds.associate::<usize>(count_expr);
let result: usize = associated.get().await?;

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl ExprDataSource for MockTableSource

async fn execute(&self, expr: &Expression<Value>) -> Result<Value, VantageError>

fn defer(&self, expr: Expression<Value>) -> DeferredFn<Value>

where Value: Clone + Send + Sync + 'static,

Implementors

impl ExprDataSource for MockExprDataSource

impl ExprDataSource for MockBuilder

impl ExprDataSource<AnySqliteType> for SqliteDB