Struct Relation 

pub struct Relation<M, T> { /* private fields */ }

A foreign key of model M pointing at T, together with access to its slot in M, so loaders can store the related object in the struct:

let relation = Relation::new(Book::author, |book| &mut book.author);
let books = Book::objects(&db).select_related(relation).all().await?;
books[0].author.cached(); // Some(&Author)

Chain relations with then for multi-hop select_related.

Implementations

impl<M: Model, T: Model> Relation<M, T>

pub fn new<S: FkSlot<T> + 'static>( field: Field<M, S>, slot: fn(&mut M) -> &mut S, ) -> Self

Relation through field; slot returns the struct field holding it: Relation::new(Book::author, |b| &mut b.author). Works for ForeignKey<T> and Option<ForeignKey<T>> slots.

pub fn then<U: Model>(self, next: Relation<T, U>) -> Relation<M, U>

Continue through a relation of T: author.then(team) reaches book.author.team.

Trait Implementations

impl<M, T> Clone for Relation<M, T>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<M: Model, T: Model> From<Relation<M, T>> for Prefetch<M, T>

fn from(relation: Relation<M, T>) -> Self

Converts to this type from the input type.