Trait datafusion_expr::expr_schema::ExprSchemable

pub trait ExprSchemable {
    // Required methods
    fn get_type(&self, schema: &dyn ExprSchema) -> Result<DataType>;
    fn nullable(&self, input_schema: &dyn ExprSchema) -> Result<bool>;
    fn metadata(
        &self,
        schema: &dyn ExprSchema,
    ) -> Result<HashMap<String, String>>;
    fn to_field(
        &self,
        input_schema: &dyn ExprSchema,
    ) -> Result<(Option<TableReference>, Arc<Field>)>;
    fn cast_to(
        self,
        cast_to_type: &DataType,
        schema: &dyn ExprSchema,
    ) -> Result<Expr>;
    fn data_type_and_nullable(
        &self,
        schema: &dyn ExprSchema,
    ) -> Result<(DataType, bool)>;
}

trait to allow expr to typable with respect to a schema

Required Methods

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

given a schema, return the type of the expr

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

given a schema, return the nullability of the expr

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

given a schema, return the expr’s optional metadata

fn to_field( &self, input_schema: &dyn ExprSchema, ) -> Result<(Option<TableReference>, Arc<Field>)>

convert to a field with respect to a schema

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

cast to a type with respect to a schema

fn data_type_and_nullable( &self, schema: &dyn ExprSchema, ) -> Result<(DataType, bool)>

given a schema, return the type and nullability of the expr

Implementors

impl ExprSchemable for Expr