Enum Parent 

pub enum Parent<T, Pk> {
    Auto,
    Template(T),
    Existing(Pk),
}

A required parent reference — the template field behind a non-null foreign key.

The default is Auto: at create time the parent’s own default template is created first (recursively — a comment chains a post chains a user) and the FK takes the created row’s key. That is the schema-aware promise: create_many(&db, 10) on the deepest table makes the whole chain exist, ten times over, each row with its own parents (FactoryBot’s association semantics — share a parent by passing it in as Existing instead).

build() (no database) fills the FK column only for Existing; Auto and Template need a database to produce a key, so build() leaves the column unset — recorded in the crate docs.

Variants

Auto

Create the parent from its default template.

Template(T)

Create the parent from this shaped template — for_post(…).

Existing(Pk)

Use this already-existing row’s key — post(&p) / post_id(k).

Trait Implementations

impl<T: Clone, Pk: Clone> Clone for Parent<T, Pk>

fn clone(&self) -> Parent<T, Pk>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Debug, Pk: Debug> Debug for Parent<T, Pk>

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

Formats the value using the given formatter.

impl<T, Pk> Default for Parent<T, Pk>

fn default() -> Self

Returns the “default value” for a type.

impl<T: PartialEq, Pk: PartialEq> PartialEq for Parent<T, Pk>

fn eq(&self, other: &Parent<T, Pk>) -> bool

Equality operator ==.

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

Inequality operator !=.

impl<T: PartialEq, Pk: PartialEq> StructuralPartialEq for Parent<T, Pk>