import { Table, Vector } from 'apache-arrow';
import { type AsyncDuckDB, type AsyncDuckDBConnection } from '@duckdb/duckdb-wasm';
export type WasmDuckDBConnection = {
    duckdb: AsyncDuckDB;
    connection?: AsyncDuckDBConnection;
};
/**
 * The `DuckDBInstance` class manages a DuckDB database instance, providing methods to interact with the database such as executing queries, uploading files, and managing tables.
 * @param {AsyncDuckDB} duckDB - The DuckDB instance.
 * @param {AsyncDuckDBConnection} duckDBConnection - The connection to the DuckDB instance.
 */
export declare class DuckDBInstance {
    private static _instance;
    private static _initPromise;
    private _db;
    private _connection;
    private constructor();
    static getInstance(): Promise<DuckDBInstance>;
    private _init;
    get connection(): AsyncDuckDBConnection;
    get db(): AsyncDuckDB;
    destroy(): Promise<void>;
    dropTable(tableName: string): Promise<void>;
    query(query: string): Promise<Table | undefined>;
    exec(query: string): Promise<void>;
    send(query: string, callback: (result: Vector) => void): Promise<void>;
    uploadData(data: File | string | Uint8Array | Table | ArrayBuffer | Record<string, unknown>[], tableName: string, insert?: boolean, csvParseTimeFormat?: string, csvColumns?: Record<string, string>): Promise<{
        error?: unknown;
    }>;
    uploadArrow(table: Uint8Array | ArrayBuffer | Table, tableName: string): Promise<{
        error?: unknown;
    }>;
    exportTableToArrow(tableName: string): Promise<Table | undefined>;
    exportTableToArrowBuffer(tableName: string): Promise<Uint8Array | undefined>;
    exportTableToPq(tableName: string): Promise<Uint8Array | undefined>;
    exportTableToCSV(tableName: string): Promise<Uint8Array | undefined>;
    uploadObject(data: Record<string, unknown>[], tableName: string, insert?: boolean): Promise<{
        error?: unknown;
    }>;
    private _uploadCSV;
    private _uploadParquet;
    private _uploadArrow;
    private _uploadJSON;
    private _handleTableInsertion;
    logTable: (tableName: string, full?: boolean) => Promise<void>;
}