Enum ColumnLineageKind 

pub enum ColumnLineageKind {
    Passthrough,
    Transformation,
}

How a source column contributes to its target — the one clean, exclusive distinction: is the value forwarded unchanged, or derived?

Finer sub-classification of Transformation (aggregate vs scalar, cardinality, etc.) is deliberately not modelled — it is lossy for edge cases (window aggregates, value-preserving STRING_AGG) and not load-bearing for the core dependency / impact-analysis use case. A finer variant can be added later if a concrete consumer needs it (a breaking change while the crate is pre-1.0).

Variants

Passthrough

Source value forwarded unchanged (SELECT a FROM t1, INSERT INTO t1 (a) SELECT b FROM t2). A rename (SELECT a AS b) is still Passthrough — detect it by comparing source / target name. Composition stays Passthrough only when every step in the chain is.

Transformation

Source feeds an expression that changes the value: arithmetic, function calls, CASE branches, casts, aggregates (SUM, STRING_AGG), window functions, etc. Composition yields Transformation whenever any step in the chain is one.

Trait Implementations

impl Clone for ColumnLineageKind

fn clone(&self) -> ColumnLineageKind

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for ColumnLineageKind

impl Debug for ColumnLineageKind

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

Formats the value using the given formatter.

impl Eq for ColumnLineageKind

impl Hash for ColumnLineageKind

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 ColumnLineageKind

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for ColumnLineageKind