Struct datafusion::catalog::listing_schema::ListingSchemaProvider

pub struct ListingSchemaProvider { /* private fields */ }

A SchemaProvider that scans an ObjectStore to automatically discover tables

A subfolder relationship is assumed, i.e. given: authority = s3://host.example.com:3000 path = /data/tpch factory = DeltaTableFactory

A table called “customer” will be registered for the folder: s3://host.example.com:3000/data/tpch/customer

assuming it contains valid deltalake data, i.e: s3://host.example.com:3000/data/tpch/customer/part-00000-xxxx.snappy.parquet s3://host.example.com:3000/data/tpch/customer/_delta_log/

Implementations

impl ListingSchemaProvider

pub fn new( authority: String, path: Path, factory: Arc<dyn TableProviderFactory>, store: Arc<dyn ObjectStore>, format: String, has_header: bool ) -> Self

Create a new ListingSchemaProvider

Arguments: authority: The scheme (i.e. s3://) + host (i.e. example.com:3000) path: The root path that contains subfolders which represent tables factory: The TableProviderFactory to use to instantiate tables for each subfolder store: The ObjectStore containing the table data format: The FileFormat of the tables has_header: Indicates whether the created external table has the has_header flag enabled

pub async fn refresh(&self, state: &SessionState) -> Result<()>

Reload table information from ObjectStore

Trait Implementations

impl SchemaProvider for ListingSchemaProvider

fn as_any(&self) -> &dyn Any

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

fn table_names(&self) -> Vec<String>

Retrieves the list of available table names in this schema.

fn table<'life0, 'life1, 'async_trait>( &'life0 self, name: &'life1 str ) -> Pin<Box<dyn Future<Output = Option<Arc<dyn TableProvider>>> + Send + 'async_trait>>where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Retrieves a specific table from the schema by name, provided it exists.

fn register_table( &self, name: String, table: Arc<dyn TableProvider> ) -> Result<Option<Arc<dyn TableProvider>>>

If supported by the implementation, adds a new table to this schema. If a table of the same name existed before, it returns “Table already exists” error.

fn deregister_table(&self, name: &str) -> Result<Option<Arc<dyn TableProvider>>>

If supported by the implementation, removes an existing table from this schema and returns it. If no table of that name exists, returns Ok(None).

fn table_exist(&self, name: &str) -> bool

If supported by the implementation, checks the table exist in the schema provider or not. If no matched table in the schema provider, return false. Otherwise, return true.