Struct mz_transform::redundant_join::ProvInfo

pub struct ProvInfo {
    id: Id,
    dereferenced_projection: Vec<Option<MirScalarExpr>>,
    exact: bool,
}

A relationship between a collections columns and some source columns.

An instance of this type indicates that some of the bearer’s columns derive from id. In particular, the non-None elements in dereferenced_projection correspond to columns that can be derived from id’s projection.

The guarantee is that projected on to these columns, the distinct values of the bearer are contained in the set of distinct values of projected columns of id. In the case that exact is set, the two sets are equal.

Fields

id: Id

The Id (local or global) of the source.

dereferenced_projection: Vec<Option<MirScalarExpr>>

The projection of the bearer written in terms of the columns projected by the underlying Get operator. Set to None for columns that cannot be expressed as scalar expression referencing only columns of the underlying Get operator.

exact: bool

If true, all distinct projected source rows are present in the rows of the projection of the current collection. This constraint is lost as soon as a transformation may drop records.

Implementations

impl ProvInfo

fn make_leaf(id: Id, arity: usize) -> Self

fn dereference(&self, expr: &MirScalarExpr) -> Option<MirScalarExpr>

Rewrite expr so it refers to the columns of the original source instead of the columns of the projected source.

fn strict_dereference(&self, expr: &MirScalarExpr) -> Option<MirScalarExpr>

Like dereference but only returns expressions that actually depend on the original source.

fn meet(&self, other: &Self) -> Option<Self>

Merge two constraints to find a constraint that satisfies both inputs.

This method returns nothing if no columns are in common (either because difference sources are identified, or just no columns in common) and it intersects bindings and the exact bit.

fn is_trivial(&self) -> bool

Check if all entries of the dereferenced projection are missing.

If this is the case keeping the ProvInfo entry around is meaningless.

Trait Implementations

impl Clone for ProvInfo

fn clone(&self) -> ProvInfo

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for ProvInfo

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

Formats the value using the given formatter.

impl Ord for ProvInfo

fn cmp(&self, other: &ProvInfo) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized + PartialOrd,

Restrict a value to a certain interval.

impl PartialEq for ProvInfo

fn eq(&self, other: &ProvInfo) -> 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 ProvInfo

fn partial_cmp(&self, other: &ProvInfo) -> 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 Eq for ProvInfo

impl StructuralPartialEq for ProvInfo