Struct Literal 

pub struct Literal {
    value: ScalarValue,
    field: Arc<Field>,
}

Represents a literal value

Fields

value: ScalarValue

field: Arc<Field>

Implementations

impl Literal

pub fn new(value: ScalarValue) -> Literal

Create a literal value expression

pub fn new_with_metadata( value: ScalarValue, metadata: Option<FieldMetadata>, ) -> Literal

Create a literal value expression

pub fn value(&self) -> &ScalarValue

Get the scalar value

Trait Implementations

impl Clone for Literal

fn clone(&self) -> Literal

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Literal

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

Formats the value using the given formatter.

impl Display for Literal

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

Formats the value using the given formatter.

impl Hash for Literal

fn hash<H>(&self, state: &mut H)

where H: Hasher,

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 Literal

fn eq(&self, other: &Literal) -> 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 PhysicalExpr for Literal

fn as_any(&self) -> &(dyn Any + 'static)

Return a reference to Any that can be used for downcasting

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

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

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

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

fn return_field( &self, _input_schema: &Schema, ) -> Result<Arc<Field>, DataFusionError>

The output field associated with this expression

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

Evaluate an expression against a RecordBatch

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<Literal>, _children: Vec<Arc<dyn PhysicalExpr>>, ) -> Result<Arc<dyn PhysicalExpr>, DataFusionError>

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

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

Format this PhysicalExpr in nice human readable “SQL” format

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

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

fn snapshot_generation(&self) -> u64

Returns the generation of this PhysicalExpr for snapshotting purposes. The generation is an arbitrary u64 that can be used to track changes in the state of the PhysicalExpr over time without having to do an exhaustive comparison. This is useful to avoid unnecessary computation or serialization if there are no changes to the expression. In particular, dynamic expressions that may change over time; this allows cheap checks for changes. Static expressions that do not change over time should return 0, as does the default implementation. You should not call this method directly as it does not handle recursion. Instead use snapshot_generation to handle recursion and capture the full state of the PhysicalExpr.

fn is_volatile_node(&self) -> bool

Returns true if the expression node is volatile, i.e. whether it can return different results when evaluated multiple times with the same input.

impl Eq for Literal

impl StructuralPartialEq for Literal