Enum Cardinality 

#[non_exhaustive]
pub enum Cardinality {
    OneToMany,
    ManyToOne,
    OneToOne,
}

Relationship cardinality between REST resources.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

OneToMany

Parent has many children (array embed).

ManyToOne

Child points to one parent (object embed).

OneToOne

Exactly one related resource (object or null).

Implementations

impl Cardinality

pub const fn is_to_one(self) -> bool

Whether an embed of this cardinality answers with one object rather than a collection.

The two object cardinalities are the ones whose join key must identify at most one target row, because there is no second row for the answer to carry; see relationship_violations.

Stated here for the reason Relationship::parent_join_column is: a caller keeping its own copy of which variants are “to-one” would classify a future variant silently, and the two opinions would drift.

Trait Implementations

impl Clone for Cardinality

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Cardinality

impl Debug for Cardinality

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Cardinality

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for Cardinality

impl PartialEq for Cardinality

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

Equality operator ==.

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

Inequality operator !=.

impl Serialize for Cardinality

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for Cardinality