Trait DataFrameBackend 

pub trait DataFrameBackend: Send + Sync {
    // Required methods
    fn as_any(&self) -> &(dyn Any + Send + Sync);
    fn filter(
        &self,
        condition: &ExprIr,
    ) -> Result<Box<dyn DataFrameBackend>, EngineError>;
    fn select(
        &self,
        exprs: &[ExprIr],
    ) -> Result<Box<dyn DataFrameBackend>, EngineError>;
    fn select_columns(
        &self,
        columns: &[&str],
    ) -> Result<Box<dyn DataFrameBackend>, EngineError>;
    fn with_column(
        &self,
        name: &str,
        expr: &ExprIr,
    ) -> Result<Box<dyn DataFrameBackend>, EngineError>;
    fn join(
        &self,
        other: &dyn DataFrameBackend,
        on: &[&str],
        how: JoinType,
    ) -> Result<Box<dyn DataFrameBackend>, EngineError>;
    fn group_by(
        &self,
        column_names: &[&str],
    ) -> Result<Box<dyn GroupedDataBackend>, EngineError>;
    fn order_by(
        &self,
        column_names: &[&str],
        ascending: &[bool],
    ) -> Result<Box<dyn DataFrameBackend>, EngineError>;
    fn limit(&self, n: usize) -> Result<Box<dyn DataFrameBackend>, EngineError>;
    fn union(
        &self,
        other: &dyn DataFrameBackend,
    ) -> Result<Box<dyn DataFrameBackend>, EngineError>;
    fn union_by_name(
        &self,
        other: &dyn DataFrameBackend,
        allow_missing_columns: bool,
    ) -> Result<Box<dyn DataFrameBackend>, EngineError>;
    fn distinct(
        &self,
        subset: Option<Vec<&str>>,
    ) -> Result<Box<dyn DataFrameBackend>, EngineError>;
    fn drop_columns(
        &self,
        columns: &[&str],
    ) -> Result<Box<dyn DataFrameBackend>, EngineError>;
    fn with_column_renamed(
        &self,
        old_name: &str,
        new_name: &str,
    ) -> Result<Box<dyn DataFrameBackend>, EngineError>;
    fn cross_join(
        &self,
        other: &dyn DataFrameBackend,
    ) -> Result<Box<dyn DataFrameBackend>, EngineError>;
    fn collect(&self) -> Result<CollectedRows, EngineError>;
    fn schema(&self) -> Result<StructType, EngineError>;
    fn columns(&self) -> Result<Vec<String>, EngineError>;
    fn count(&self) -> Result<u64, EngineError>;
}

Backend for DataFrame operations. All expression arguments use ExprIr. Implementors can be downcast via as_any() for backend-specific operations (e.g. join).

Required Methods

fn as_any(&self) -> &(dyn Any + Send + Sync)

For downcasting to concrete backend type (e.g. for join with same backend).

fn filter( &self, condition: &ExprIr, ) -> Result<Box<dyn DataFrameBackend>, EngineError>

fn select( &self, exprs: &[ExprIr], ) -> Result<Box<dyn DataFrameBackend>, EngineError>

fn select_columns( &self, columns: &[&str], ) -> Result<Box<dyn DataFrameBackend>, EngineError>

fn with_column( &self, name: &str, expr: &ExprIr, ) -> Result<Box<dyn DataFrameBackend>, EngineError>

fn join( &self, other: &dyn DataFrameBackend, on: &[&str], how: JoinType, ) -> Result<Box<dyn DataFrameBackend>, EngineError>

fn group_by( &self, column_names: &[&str], ) -> Result<Box<dyn GroupedDataBackend>, EngineError>

fn order_by( &self, column_names: &[&str], ascending: &[bool], ) -> Result<Box<dyn DataFrameBackend>, EngineError>

fn limit(&self, n: usize) -> Result<Box<dyn DataFrameBackend>, EngineError>

fn union( &self, other: &dyn DataFrameBackend, ) -> Result<Box<dyn DataFrameBackend>, EngineError>

fn union_by_name( &self, other: &dyn DataFrameBackend, allow_missing_columns: bool, ) -> Result<Box<dyn DataFrameBackend>, EngineError>

fn distinct( &self, subset: Option<Vec<&str>>, ) -> Result<Box<dyn DataFrameBackend>, EngineError>

fn drop_columns( &self, columns: &[&str], ) -> Result<Box<dyn DataFrameBackend>, EngineError>

fn with_column_renamed( &self, old_name: &str, new_name: &str, ) -> Result<Box<dyn DataFrameBackend>, EngineError>

fn cross_join( &self, other: &dyn DataFrameBackend, ) -> Result<Box<dyn DataFrameBackend>, EngineError>

fn collect(&self) -> Result<CollectedRows, EngineError>

fn schema(&self) -> Result<StructType, EngineError>

fn columns(&self) -> Result<Vec<String>, EngineError>

fn count(&self) -> Result<u64, EngineError>

Implementors