Struct UnboundColumn

pub struct UnboundColumn { /* private fields */ }

This is similar to UnKnownColumn in DataFusion, but it has data type. This is only used when the column is not bound to a schema, for example, the inputs to aggregation functions in final aggregation. In the case, we cannot bind the aggregation functions to the input schema which is grouping columns and aggregate buffer attributes in Spark (DataFusion has different design). But when creating certain aggregation functions, we need to know its input data types. As UnKnownColumn doesn’t have data type, we implement this UnboundColumn to carry the data type.

Implementations

impl UnboundColumn

pub fn new(name: &str, datatype: DataType) -> Self

Create a new unbound column expression

pub fn name(&self) -> &str

Get the column name

Trait Implementations

impl Clone for UnboundColumn

fn clone(&self) -> UnboundColumn

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for UnboundColumn

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

Formats the value using the given formatter.

impl Display for UnboundColumn

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

Formats the value using the given formatter.

impl Hash for UnboundColumn

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 UnboundColumn

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

Tests for self and other values to be equal, and is used by ==.

const 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 PhysicalExpr for UnboundColumn

fn as_any(&self) -> &dyn Any

Return a reference to Any that can be used for downcasting

fn data_type(&self, _input_schema: &Schema) -> Result<DataType>

Get the data type of this expression, given the schema of the input

fn nullable(&self, _input_schema: &Schema) -> Result<bool>

Decide whether this expression is nullable, given the schema of the input

fn evaluate(&self, _batch: &RecordBatch) -> Result<ColumnarValue>

Evaluate the expression

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

Format this PhysicalExpr in nice human readable “SQL” format

fn children(&self) -> Vec<&Arc<dyn PhysicalExpr>>

Get a list of child PhysicalExpr that provide the input for this expr.

fn with_new_children( self: Arc<Self>, _children: Vec<Arc<dyn PhysicalExpr>>, ) -> Result<Arc<dyn PhysicalExpr>>

Returns a new PhysicalExpr where all children were replaced by new exprs.

fn evaluate_selection( &self, batch: &RecordBatch, selection: &BooleanArray, ) -> Result<ColumnarValue, DataFusionError>

Evaluate an expression against a RecordBatch after first applying a validity array

fn evaluate_bounds( &self, _children: &[&Interval], ) -> Result<Interval, DataFusionError>

Computes the output interval for the expression, given the input intervals.

fn propagate_constraints( &self, _interval: &Interval, _children: &[&Interval], ) -> Result<Option<Vec<Interval>>, DataFusionError>

Updates bounds for child expressions, given a known interval for this expression.

fn evaluate_statistics( &self, children: &[&Distribution], ) -> Result<Distribution, DataFusionError>

Computes the output statistics for the expression, given the input statistics.

fn propagate_statistics( &self, parent: &Distribution, children: &[&Distribution], ) -> Result<Option<Vec<Distribution>>, DataFusionError>

Updates children statistics using the given parent statistic for this expression.

fn get_properties( &self, _children: &[ExprProperties], ) -> Result<ExprProperties, DataFusionError>

Calculates the properties of this PhysicalExpr based on its children’s properties (i.e. order and range), recursively aggregating the information from its children. In cases where the PhysicalExpr has no children (e.g., Literal or Column), these properties should be specified externally, as the function defaults to unknown properties.

fn snapshot(&self) -> Result<Option<Arc<dyn PhysicalExpr>>, DataFusionError>

Take a snapshot of this PhysicalExpr, if it is dynamic.

impl Eq for UnboundColumn

impl StructuralPartialEq for UnboundColumn