ClickHouse/src/Storages/StorageXDBC.h

#pragma once

#include <Storages/StorageURL.h>
#include <Common/XDBCBridgeHelper.h>


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:
    Pipes read(
        const Names & column_names,
        const StorageMetadataPtr & /*metadata_snapshot*/,
        const SelectQueryInfo & query_info,
        const Context & 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,
                const ColumnsDescription & columns_,
                const Context & context_, BridgeHelperPtr bridge_helper_);

    BlockOutputStreamPtr write(const ASTPtr & query, const StorageMetadataPtr & /*metadata_snapshot*/, const Context & context) 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 SelectQueryInfo & query_info,
                                                                        const Context & context,
                                                                        QueryProcessingStage::Enum & processed_stage,
                                                                        size_t max_block_size) const override;

    std::function<void(std::ostream &)> getReadPOSTDataCallback(const Names & column_names,
                                                                const SelectQueryInfo & query_info,
                                                                const Context & context,
                                                                QueryProcessingStage::Enum & processed_stage,
                                                                size_t max_block_size) const override;

    Block getHeaderBlock(const Names & column_names) const override;

    std::string getName() const override;
};

}