Struct datafusion::datasource::empty::EmptyTable

pub struct EmptyTable { /* private fields */ }

A table with a schema but no data.

Implementations

impl EmptyTable

pub fn new(schema: SchemaRef) -> Self

Initialize a new EmptyTable from a schema.

Trait Implementations

impl TableProvider for EmptyTable

fn as_any(&self) -> &dyn Any

Returns the table provider as Any so that it can be downcast to a specific implementation.

fn schema(&self) -> SchemaRef

Get a reference to the schema for this table

fn scan<'life0, 'life1, 'life2, 'async_trait>(
    &'life0 self,
    projection: &'life1 Option<Vec<usize>>,
    _filters: &'life2 [Expr],
    _limit: Option<usize>
) -> Pin<Box<dyn Future<Output = Result<Arc<dyn ExecutionPlan>>> + Send + 'async_trait>> where
    'life0: 'async_trait,
    'life1: 'async_trait,
    'life2: 'async_trait,
    Self: 'async_trait, 

Create an ExecutionPlan that will scan the table. The table provider will be usually responsible of grouping the source data into partitions that can be efficiently parallelized or distributed.

fn table_type(&self) -> TableType

Get the type of this table for metadata/catalog purposes.

fn supports_filter_pushdown(
    &self,
    _filter: &Expr
) -> Result<TableProviderFilterPushDown>

Tests whether the table provider can make use of a filter expression to optimise data retrieval.