Enum Cardinality 

pub enum Cardinality {
    Single,
    Optional,
    Repeated,
    Map {
        key: LogicalType,
    },
}

How many values a field holds.

Variants

Single

Exactly one (proto3 singular).

Optional

Zero or one (proto3 optional, a message-typed singular field).

Repeated

Zero or more (repeated).

Map

A keyed collection; the value type is the field’s logical.

Fields

key: LogicalType

Trait Implementations

impl Clone for Cardinality

fn clone(&self) -> Cardinality

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Cardinality

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

Formats the value using the given formatter.

impl PartialEq for Cardinality

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for Cardinality

impl StructuralPartialEq for Cardinality