Struct datafusion_optimizer::simplify_expressions::context::SimplifyContext

pub struct SimplifyContext<'a> { /* private fields */ }

Provides simplification information based on DFSchema and ExecutionProps. This is the default implementation used by DataFusion

For example:

use arrow::datatypes::{Schema, Field, DataType};
use datafusion_expr::{col, lit};
use datafusion_common::{DataFusionError, ToDFSchema};
use datafusion_physical_expr::execution_props::ExecutionProps;
use datafusion_optimizer::simplify_expressions::{SimplifyContext, ExprSimplifier};

// Create the schema
let schema = Schema::new(vec![
    Field::new("i", DataType::Int64, false),
  ])
  .to_dfschema_ref().unwrap();

// Create the simplifier
let props = ExecutionProps::new();
let context = SimplifyContext::new(&props)
   .with_schema(schema);
let simplifier = ExprSimplifier::new(context);

// Use the simplifier

// b < 2 or (1 > 3)
let expr = col("b").lt(lit(2)).or(lit(1).gt(lit(3)));

// b < 2
let simplified = simplifier.simplify(expr).unwrap();
assert_eq!(simplified, col("b").lt(lit(2)));

Implementations

impl<'a> SimplifyContext<'a>

pub fn new(props: &'a ExecutionProps) -> Self

Create a new SimplifyContext

pub fn with_schema(self, schema: DFSchemaRef) -> Self

Register a DFSchemaRef with this context

Trait Implementations

impl<'a> SimplifyInfo for SimplifyContext<'a>

fn is_boolean_type(&self, expr: &Expr) -> Result<bool>

returns true if this Expr has boolean type

fn nullable(&self, expr: &Expr) -> Result<bool>

Returns true if expr is nullable

fn get_data_type(&self, expr: &Expr) -> Result<DataType>

Returns data type of this expr needed for determining optimized int type of a value

fn execution_props(&self) -> &ExecutionProps

Returns details needed for partial expression evaluation