Trait datafusion_expr::expr_schema::ExprSchemable

pub trait ExprSchemable {
    // Required methods
    fn get_type<S: ExprSchema>(&self, schema: &S) -> Result<DataType>;
    fn nullable<S: ExprSchema>(&self, input_schema: &S) -> Result<bool>;
    fn metadata<S: ExprSchema>(
        &self,
        schema: &S
    ) -> Result<HashMap<String, String>>;
    fn to_field(&self, input_schema: &DFSchema) -> Result<DFField>;
    fn cast_to<S: ExprSchema>(
        self,
        cast_to_type: &DataType,
        schema: &S
    ) -> Result<Expr>;
}

trait to allow expr to typable with respect to a schema

Required Methods

fn get_type<S: ExprSchema>(&self, schema: &S) -> Result<DataType>

given a schema, return the type of the expr

fn nullable<S: ExprSchema>(&self, input_schema: &S) -> Result<bool>

given a schema, return the nullability of the expr

fn metadata<S: ExprSchema>(&self, schema: &S) -> Result<HashMap<String, String>>

given a schema, return the expr’s optional metadata

fn to_field(&self, input_schema: &DFSchema) -> Result<DFField>

convert to a field with respect to a schema

fn cast_to<S: ExprSchema>( self, cast_to_type: &DataType, schema: &S ) -> Result<Expr>

cast to a type with respect to a schema

Implementors

impl ExprSchemable for Expr