Trait diesel::expression::BoxableExpression

pub trait BoxableExpression<QS, DB> where DB: Backend,
               Self: Expression,
               Self: SelectableExpression<QS>,
               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, STS, DB> QueryId for BoxableExpression<QS, DB, SqlType=ST, SqlTypeForSelect=STS>

type QueryId = ()

fn has_static_query_id() -> bool

fn query_id() -> Option<TypeId>

Implementors

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