Struct ReverseSet 

pub struct ReverseSet<C: Model> { /* private fields */ }

A reverse-FK collection field on a parent model. The framework fills resolved via .prefetch_related(field_name); without that chain method resolved() returns None and set_parent_id / set_fk_column stay unset (the field is inert).

Implementations

impl<C: Model> ReverseSet<C>

pub fn empty() -> Self

Construct an empty (unloaded, no parent yet) ReverseSet.

pub fn resolved(&self) -> Option<&[C]>

Borrow the resolved children as a slice. None means prefetch wasn’t called for this field; the framework never silently loads children on first access (no lazy loading by design — Rust has no property accessors to intercept and hidden round-trips are surprising).

pub fn set_parent_id(&mut self, id: Value)

Set the parent’s PK on this slot so the prefetch loader knows which WHERE <fk_column> = parent_pk bucket to target. Called by the macro-emitted set_m2m_parent_ids arm with the parent’s PK as a serde_json::Value (PK lift — was i64).

pub fn set_fk_column(&mut self, col: &'static str)

Set the FK column name on the child. Called by the same macro hook from the #[umbral(reverse_fk = "...")] attribute.

pub fn parent_link(&self) -> Option<(&Value, &'static str)>

Read the parent PK + FK column the prefetch loader needs. None for either means this slot was never wired up (the macro didn’t see a #[umbral(reverse_fk = ...)] attribute, or set_m2m_parent_ids wasn’t called yet). Returns Option<(parent_id, fk_column)> so the caller can early-exit without a separate isset check.

pub fn set_resolved(&mut self, rows: Vec<C>)

Populate the resolved bucket. Called once by the prefetch loader after grouping the batched child rows by fk_column value.

Trait Implementations

impl<C: Clone + Model> Clone for ReverseSet<C>

fn clone(&self) -> ReverseSet<C>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<C: Debug + Model> Debug for ReverseSet<C>

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

Formats the value using the given formatter.

impl<'r, C: Model> Decode<'r, Postgres> for ReverseSet<C>

fn decode(value: PgValueRef<'r>) -> Result<Self, Box<dyn Error + Send + Sync>>

Decode a new value of this type using a raw value from the database.

impl<'r, C: Model> Decode<'r, Sqlite> for ReverseSet<C>

fn decode( value: SqliteValueRef<'r>, ) -> Result<Self, Box<dyn Error + Send + Sync>>

Decode a new value of this type using a raw value from the database.

impl<C: Model> Default for ReverseSet<C>

Default is what the sqlx::FromRow #[sqlx(skip)] path uses to fill the slot. HydrateRelated::set_m2m_parent_ids then seeds parent_id + fk_column from the just-decoded parent row.

fn default() -> Self

Returns the “default value” for a type.

impl<'de, C: Model + Deserialize<'de>> Deserialize<'de> for ReverseSet<C>

Deserialize: accepts a JSON array of C (the already-resolved shape). Round-trip support for a prefetched parent. Tolerates null / missing by returning an unloaded default — the same shape #[serde(skip)] would produce.

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

Deserialize this value from the given Serde deserializer.

impl<C: Model + Serialize> Serialize for ReverseSet<C>

Serialize: emit the resolved children (or [] if not yet loaded). Symmetric with M2M’s shape so templates / REST serialisation doesn’t surprise users with null for unloaded slots.

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

Serialize this value into the given Serde serializer.

impl<C: Model> Type<Postgres> for ReverseSet<C>

fn type_info() -> PgTypeInfo

Returns the canonical SQL type for this Rust type.

fn compatible(ty: &PgTypeInfo) -> bool

Determines if this Rust type is compatible with the given SQL type.

impl<C: Model> Type<Sqlite> for ReverseSet<C>

fn type_info() -> SqliteTypeInfo

Returns the canonical SQL type for this Rust type.

fn compatible(ty: &SqliteTypeInfo) -> bool

Determines if this Rust type is compatible with the given SQL type.