Trait cqrs_es2::Query

pub trait Query<A: Aggregate>: Debug + Default + Serialize + DeserializeOwned {
    fn update(&mut self, event: &EventEnvelope<A>);
}

A Query is a read element in a CQRS system. As events are emitted multiple downstream queries are updated to reflect the current state of the system. A query may also be referred to as a ‘view’, the concepts are identical but ‘query’ is used here to conform with CQRS nomenclature.

Queries are generally serialized for persistence, usually in a standard database, but a query could also utilize messaging platform or other asynchronous, eventually-consistent systems.

Required methods

fn update(&mut self, event: &EventEnvelope<A>)

Each implemented query is responsible for updating its stated based on events passed via this method.

Implementors