Struct datafusion_physical_expr::equivalence::ProjectionMapping

pub struct ProjectionMapping { /* private fields */ }

Stores the mapping between source expressions and target expressions for a projection.

Implementations

impl ProjectionMapping

pub fn try_new( expr: &[(Arc<dyn PhysicalExpr>, String)], input_schema: &SchemaRef ) -> Result<Self>

Constructs the mapping between a projection’s input and output expressions.

For example, given the input projection expressions (a+b, c+d) and an output schema with two columns "c+d" and "a+b" the projection mapping would be

 [0]: (c+d, col("c+d"))
 [1]: (a+b, col("a+b"))

where col("c+d") means the column named “c+d”.

pub fn iter( &self ) -> impl Iterator<Item = &(Arc<dyn PhysicalExpr>, Arc<dyn PhysicalExpr>)> + '_

Iterate over pairs of (source, target) expressions

Trait Implementations

impl Clone for ProjectionMapping

fn clone(&self) -> ProjectionMapping

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for ProjectionMapping

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

Formats the value using the given formatter.