Enum NullEquality

pub enum NullEquality {
    NullEqualsNothing,
    NullEqualsNull,
}

Represents the behavior for null values when evaluating equality. Currently, its primary use case is to define the behavior of joins for null values.

Examples

The following table shows the expected equality behavior for NullEquality.

A	B	NullEqualsNothing	NullEqualsNull
NULL	NULL	false	true
NULL	‘b’	false	false
‘a’	NULL	false	false
‘a’	‘b’	false	false

Order

The order on this type represents the “restrictiveness” of the behavior. The more restrictive a behavior is, the fewer elements are considered to be equal to null. NullEquality::NullEqualsNothing represents the most restrictive behavior.

This mirrors the old order with null_equals_null booleans, as false indicated that null != null.

Variants

NullEqualsNothing

Null is not equal to anything (null != null)

NullEqualsNull

Null is equal to null (null == null)

Trait Implementations

impl Clone for NullEquality

fn clone(&self) -> NullEquality

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for NullEquality

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

Formats the value using the given formatter.

impl Hash for NullEquality

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for NullEquality

fn eq(&self, other: &NullEquality) -> 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 PartialOrd for NullEquality

fn partial_cmp(&self, other: &NullEquality) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for NullEquality

impl Eq for NullEquality

impl StructuralPartialEq for NullEquality