Struct ForeignKey 

pub struct ForeignKey<T: Model> { /* private fields */ }

A many-to-one reference to T stored as T’s primary key.

Serializes as the bare key ("author": 7), like Django REST framework’s default. The cached object is never serialized. [Validate], [Schema] and [Dump] follow T::Pk.

Implementations

impl<T: Model> ForeignKey<T>

pub fn new(id: T::Pk) -> Self

Reference by primary key (nothing is loaded).

pub fn to(object: T) -> Self

Reference an already loaded object; it becomes the cached value.

pub fn id(&self) -> &T::Pk

The referenced primary key.

pub fn cached(&self) -> Option<&T>

The cached object, if it was loaded.

pub async fn get(&self, db: &Db) -> Result<Arc<T>, OrmError>

The referenced object: the cached one, or fetched by primary key (and not cached, since self is borrowed immutably).

Errors

QueryError::DoesNotExist for a dangling key, or backend errors.

pub fn set_cached(&mut self, object: Arc<T>)

Replace the cached object. Ignored unless its key matches id, so a stale object is never attached.

Trait Implementations

impl<T: Model> Clone for ForeignKey<T>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Model> DbType for ForeignKey<T>

const SQL_TYPE: SqlType = <T::Pk as DbType>::SQL_TYPE

Column type family.

fn to_value(&self) -> Value

Convert to a bind value.

fn from_value(value: Value) -> Result<Self, String>

Decode from a value read from any backend.

const NULLABLE: bool = false

Whether the column accepts NULL (true only for Option<T>).

impl<T: Model> Debug for ForeignKey<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de, T: Model> Deserialize<'de> for ForeignKey<T>

where T::Pk: Deserialize<'de>,

fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error>

Deserialize this value from the given Serde deserializer.

impl<T: Model> Dump for ForeignKey<T>

where T::Pk: Serialize,

fn serialize_dump<S>( &self, serializer: S, opts: &DumpOptions, ) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error>

where S: Serializer,

Serialize directly when supported, preserving dump semantics.

fn dump(&self, opts: &DumpOptions) -> Result<Value, DumpError>

Serialize with opts applied.

impl<T: Model> FkSlot<T> for ForeignKey<T>

fn fk(&mut self) -> Option<&mut ForeignKey<T>>

The foreign key, if set.

impl<'a, T: Model> Literal<ForeignKey<T>> for &'a T

fn into_value(self) -> Value

Convert into a bind value.

impl<T: Model<Pk = i16>> Literal<ForeignKey<T>> for i16

fn into_value(self) -> Value

Convert into a bind value.

impl<T: Model<Pk = i32>> Literal<ForeignKey<T>> for i32

fn into_value(self) -> Value

Convert into a bind value.

impl<T: Model<Pk = i64>> Literal<ForeignKey<T>> for i64

fn into_value(self) -> Value

Convert into a bind value.

impl<T: Model<Pk = Uuid>> Literal<ForeignKey<T>> for Uuid

fn into_value(self) -> Value

Convert into a bind value.

impl<T: Model<Pk = String>> Literal<ForeignKey<T>> for String

fn into_value(self) -> Value

Convert into a bind value.

impl<'a, T: Model<Pk = String>> Literal<ForeignKey<T>> for &'a str

fn into_value(self) -> Value

Convert into a bind value.

impl<'a, T: Model, M> Operand<M, ForeignKey<T>> for &'a T

fn into_expr(self) -> Expr

Convert into an expression.

impl<T: Model<Pk = i16>, M> Operand<M, ForeignKey<T>> for i16

fn into_expr(self) -> Expr

Convert into an expression.

impl<T: Model<Pk = i32>, M> Operand<M, ForeignKey<T>> for i32

fn into_expr(self) -> Expr

Convert into an expression.

impl<T: Model<Pk = i64>, M> Operand<M, ForeignKey<T>> for i64

fn into_expr(self) -> Expr

Convert into an expression.

impl<T: Model<Pk = Uuid>, M> Operand<M, ForeignKey<T>> for Uuid

fn into_expr(self) -> Expr

Convert into an expression.

impl<T: Model<Pk = String>, M> Operand<M, ForeignKey<T>> for String

fn into_expr(self) -> Expr

Convert into an expression.

impl<'a, T: Model<Pk = String>, M> Operand<M, ForeignKey<T>> for &'a str

fn into_expr(self) -> Expr

Convert into an expression.

impl<T: Model> PartialEq for ForeignKey<T>

Equality compares keys only.

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl<T: Model + 'static> Schema for ForeignKey<T>

where T::Pk: Schema + 'static,

fn schema(registry: &mut SchemaRegistry) -> SchemaObject

The schema definition of this type. Use [SchemaRegistry::subschema] for nested types.

fn schema_name() -> Option<&'static str>

Stable component name. Named types are emitted once under components.schemas and referenced with $ref.

impl<T: Model> Serialize for ForeignKey<T>

where T::Pk: Serialize,

fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error>

Serialize this value into the given Serde serializer.

impl<T: Model> Validate for ForeignKey<T>

where T::Pk: Validate,

fn prepare(input: &mut JsonValue, ctx: &mut ValidationContext)

Check and normalise the raw input for this type in place.

fn validate(&self, ctx: &mut ValidationContext)

Check invariants of the deserialized value.