Trait SchemaAdapterFactory

pub trait SchemaAdapterFactory:
    Debug
    + Send
    + Sync
    + 'static {
    // Required method
    fn create(
        &self,
        projected_table_schema: SchemaRef,
        table_schema: SchemaRef,
    ) -> Box<dyn SchemaAdapter>;

    // Provided method
    fn create_with_projected_schema(
        &self,
        projected_table_schema: SchemaRef,
    ) -> Box<dyn SchemaAdapter> { ... }
}

Factory for creating SchemaAdapter

This interface provides a way to implement custom schema adaptation logic for DataSourceExec (for example, to fill missing columns with default value other than null).

Most users should use DefaultSchemaAdapterFactory. See that struct for more details and examples.

Required Methods

fn create( &self, projected_table_schema: SchemaRef, table_schema: SchemaRef, ) -> Box<dyn SchemaAdapter>

Create a SchemaAdapter

Arguments:

• projected_table_schema: The schema for the table, projected to include only the fields being output (projected) by the this mapping.

• table_schema: The entire table schema for the table

Provided Methods

fn create_with_projected_schema( &self, projected_table_schema: SchemaRef, ) -> Box<dyn SchemaAdapter>

Create a SchemaAdapter using only the projected table schema.

This is a convenience method for cases where the table schema and the projected table schema are the same.

Implementors

impl SchemaAdapterFactory for DefaultSchemaAdapterFactory