ClickHouse/src/Storages/StorageXDBC.h
2022-08-20 21:26:07 +03:00

75 lines
2.1 KiB
C++

#pragma once
#include <Storages/StorageURL.h>
#include <BridgeHelper/XDBCBridgeHelper.h>
namespace Poco
{
class Logger;
}
namespace DB
{
/** Implements storage in the XDBC database.
* Use ENGINE = xdbc(connection_string, table_name)
* Example ENGINE = odbc('dsn=test', table)
* Read only.
*/
class StorageXDBC : public IStorageURLBase
{
public:
Pipe read(
const Names & column_names,
const StorageSnapshotPtr & storage_snapshot,
SelectQueryInfo & query_info,
ContextPtr context,
QueryProcessingStage::Enum processed_stage,
size_t max_block_size,
unsigned num_streams) override;
StorageXDBC(
const StorageID & table_id_,
const std::string & remote_database_name,
const std::string & remote_table_name,
ColumnsDescription columns_,
ConstraintsDescription constraints_,
const String & comment,
ContextPtr context_,
BridgeHelperPtr bridge_helper_);
SinkToStoragePtr write(const ASTPtr & query, const StorageMetadataPtr & /*metadata_snapshot*/, ContextPtr context) override;
std::string getName() const override;
private:
BridgeHelperPtr bridge_helper;
std::string remote_database_name;
std::string remote_table_name;
Poco::Logger * log;
std::string getReadMethod() const override;
std::vector<std::pair<std::string, std::string>> getReadURIParams(
const Names & column_names,
const StorageSnapshotPtr & storage_snapshot,
const SelectQueryInfo & query_info,
ContextPtr context,
QueryProcessingStage::Enum & processed_stage,
size_t max_block_size) const override;
std::function<void(std::ostream &)> getReadPOSTDataCallback(
const Names & column_names,
const ColumnsDescription & columns_description,
const SelectQueryInfo & query_info,
ContextPtr context,
QueryProcessingStage::Enum & processed_stage,
size_t max_block_size) const override;
Block getHeaderBlock(const Names & column_names, const StorageSnapshotPtr & storage_snapshot) const override;
bool supportsSubsetOfColumns() const override;
};
}