Enum NullHandling 

pub enum NullHandling {
    Exclude,
    Include,
    Distinct,
}

Null handling strategy for uniqueness constraints.

Defines how NULL values should be treated when evaluating uniqueness.

Variants

Exclude

Exclude NULL values from uniqueness calculations (default behavior). NULLs are not counted in distinct counts but are included in total counts.

Include

Include NULL values as regular values in uniqueness calculations. Multiple NULLs are treated as duplicate values.

Distinct

Treat each NULL as a distinct value. Each NULL is considered unique from every other NULL.

Trait Implementations

impl Clone for NullHandling

fn clone(&self) -> NullHandling

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for NullHandling

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

Formats the value using the given formatter.

impl Default for NullHandling

fn default() -> NullHandling

Returns the “default value” for a type.

impl Display for NullHandling

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

Formats the value using the given formatter.

impl PartialEq for NullHandling

fn eq(&self, other: &NullHandling) -> 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 Copy for NullHandling

impl Eq for NullHandling

impl StructuralPartialEq for NullHandling