Trait diesel::expression::BoxableExpression

pub trait BoxableExpression<QS, ST, DB> where DB: Backend, Self: Expression, Self: SelectableExpression<QS, ST>, Self: NonAggregate, Self: QueryFragment<DB> { }

Helper trait used when boxing expressions. This exists to work around the fact that Rust will not let us use non-core types as bounds on a trait object (you could not return Box<Expression+NonAggregate>)

Trait Implementations

impl<QS, ST, DB> QueryId for BoxableExpression<QS, ST, DB, SqlType=ST>

type QueryId = ()

fn has_static_query_id() -> bool

fn query_id() -> Option<TypeId>

Implementors

• impl<QS, T, ST, DB> BoxableExpression<QS, ST, DB> for T where DB: Backend, T: Expression, T: SelectableExpression<QS, ST>, T: NonAggregate, T: QueryFragment<DB>