chDB for Rust

chDB-rust 提供实验性的 FFI（外部函数接口）绑定，用于 chDB，使您能够在 Rust 应用程序中直接运行 ClickHouse 查询，而无需任何外部依赖。

Installation

Install libchdb

安装 chDB 库：

curl -sL https://lib.chdb.io | bash

Usage

chDB Rust 提供无状态和有状态查询执行模式。

Stateless usage

对于没有持久状态的简单查询：

use chdb_rust::{execute, arg::Arg, format::OutputFormat};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Execute a simple query
    let result = execute(
        "SELECT version()",
        Some(&[Arg::OutputFormat(OutputFormat::JSONEachRow)])
    )?;
    println!("ClickHouse version: {}", result.data_utf8()?);

    // Query with CSV file
    let result = execute(
        "SELECT * FROM file('data.csv', 'CSV')",
        Some(&[Arg::OutputFormat(OutputFormat::JSONEachRow)])
    )?;
    println!("CSV data: {}", result.data_utf8()?);

    Ok(())
}

Stateful usage (Sessions)

对于需要持久状态的查询，如数据库和表：

use chdb_rust::{
    session::SessionBuilder,
    arg::Arg,
    format::OutputFormat,
    log_level::LogLevel
};
use tempdir::TempDir;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Create a temporary directory for database storage
    let tmp = TempDir::new("chdb-rust")?;

    // Build session with configuration
    let session = SessionBuilder::new()
        .with_data_path(tmp.path())
        .with_arg(Arg::LogLevel(LogLevel::Debug))
        .with_auto_cleanup(true)  // Cleanup on drop
        .build()?;

    // Create database and table
    session.execute(
        "CREATE DATABASE demo; USE demo", 
        Some(&[Arg::MultiQuery])
    )?;

    session.execute(
        "CREATE TABLE logs (id UInt64, msg String) ENGINE = MergeTree() ORDER BY id",
        None,
    )?;

    // Insert data
    session.execute(
        "INSERT INTO logs (id, msg) VALUES (1, 'Hello'), (2, 'World')",
        None,
    )?;

    // Query data
    let result = session.execute(
        "SELECT * FROM logs ORDER BY id",
        Some(&[Arg::OutputFormat(OutputFormat::JSONEachRow)]),
    )?;

    println!("Query results:\n{}", result.data_utf8()?);

    // Get query statistics
    println!("Rows read: {}", result.rows_read());
    println!("Bytes read: {}", result.bytes_read());
    println!("Query time: {:?}", result.elapsed());

    Ok(())
}

Building and testing

Build the project

cargo build

Run tests

cargo test

Development dependencies

该项目包括以下开发依赖：

• bindgen (v0.70.1) - 从 C 头文件生成 FFI 绑定
• tempdir (v0.3.7) - 在测试中处理临时目录
• thiserror (v1) - 错误处理工具

Error handling

chDB Rust 通过 Error 枚举提供全面的错误处理：

use chdb_rust::{execute, error::Error};

match execute("SELECT 1", None) {
    Ok(result) => {
        println!("Success: {}", result.data_utf8()?);
    },
    Err(Error::QueryError(msg)) => {
        eprintln!("Query failed: {}", msg);
    },
    Err(Error::NoResult) => {
        eprintln!("No result returned");
    },
    Err(Error::NonUtf8Sequence(e)) => {
        eprintln!("Invalid UTF-8: {}", e);
    },
    Err(e) => {
        eprintln!("Other error: {}", e);
    }
}

GitHub repository

您可以在 chdb-io/chdb-rust 找到该项目的 GitHub 仓库。