Struct UniquenessConstraint 

pub struct UniquenessConstraint {
    pub is_primary_key: bool,
    pub columns: Vec<usize>,
    pub nulls_not_distinct: bool,
    pub name: Option<String>,
    pub deferrable: bool,
    pub initially_deferred: bool,
}

Fields

is_primary_key: bool

true when this constraint was declared as PRIMARY KEY (vs UNIQUE). Semantically PK implies NOT NULL on all referenced columns; the engine enforces that at CREATE TABLE time.

columns: Vec<usize>

Column positions on the parent table. ≥ 1 element. For single-column UNIQUE this is exactly one position; the BTree index alone enforces it.

nulls_not_distinct: bool

v7.13.0 — UNIQUE NULLS NOT DISTINCT modifier (mailrs round-5 G10; PG 15+ surface). When true, two rows whose constrained columns are all NULL collide on the constraint. Default (false) is the SQL-standard NULLS DISTINCT behaviour where any NULL passes. Persisted in catalog FILE_VERSION 23+.

name: Option<String>

v7.39 (read01 round 48) — the constraint’s SQL name when the user supplied one (ADD CONSTRAINT <name> PRIMARY KEY/UNIQUE (...), or the inline CONSTRAINT <name> form). None = unnamed, in which case pg_constraint synthesises PG’s <table>_pkey / <table>_<col>_key form. DROP CONSTRAINT resolves the stored name first and falls back to the synthesised one, so catalogs written before this field (< FILE_VERSION 60) keep working unchanged.

deferrable: bool

v7.39 (round 711) — [NOT] DEFERRABLE. Round 621 taught the parser to CONSUME the clause on PK/UNIQUE (the FK path had stored it since round 288); this is the storing half. Persisted in the v89 timing appendix.

initially_deferred: bool

INITIALLY DEFERRED: the check belongs to COMMIT, not the statement, unless SET CONSTRAINTS … IMMEDIATE pulls it in.

Trait Implementations

impl Clone for UniquenessConstraint

fn clone(&self) -> UniquenessConstraint

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for UniquenessConstraint

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

Formats the value using the given formatter.

impl Eq for UniquenessConstraint

impl PartialEq for UniquenessConstraint

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for UniquenessConstraint