ClickHouse .NET Core driver

This is an implementation of .NET Core driver for ClickHouse in a form of ADO.NET DbProvider API. This driver supports all ADO.NET features (with some exclusions like transaction support).

Features

• supports binary protocol
• compression (send and recieve)
• timezones
• most clickhouse column types are supported (aggregating ones are under development)
• full support for .net async ADO.NET API
• no unsafe code
• tested- used in production
• c# named tuple and record support
• Dapper support (example in #19)

Usage

Install from NuGet:

dotnet add package Octonica.ClickHouseClient

ConnectionString syntax: Host=<host>;Port=<port>;Database=<db>;Password=<pass>, e.g. "Host=127.0.0.1;Password=P@ssw0rd; Database=db additionally, if you want to build a connection string via code you can use ClickHouseConnectionStringBuilder.

Entry point for API is ADO .NET DbConnection Class: Octonica.ClickHouse.ClickHouseConnection.

Extended API

In order to provide non-ADO.NET complaint data manipulation functionality, proprietary ClickHouseColumnWriter API exists. Entry point for API is ClickHouseConnection.CreateColumnWriter() method.

Simple SELECT async verison

var sb = new ClickHouseConnectionStringBuilder();
sb.Host = "127.0.0.1";
using var conn = new ClickHouseConnection(sb);
await conn.OpenAsync();
var currentUser = await conn.CreateCommand("select currentUser()").ExecuteScalarAsync();

Insert data with parameters

var sb = new ClickHouseConnectionStringBuilder();
sb.Host = "127.0.0.1";
using var conn = new ClickHouseConnection(sb);
conn.Open();
using var cmd = conn.CreateCommand("INSERT INTO table_you_just_created SELECT {id}, {dt}");
cmd.Parameters.AddWithValue("id", Guid.NewGuid());
cmd.Parameters.AddWithValue("dt", DateTime.Now, System.Data.DbType.DateTime);
var _ = cmd.ExecuteNonQuery();

For more information see Parameters.

Bulk insert

using var conn = new ClickHouseConnection("Host=127.0.0.1");
conn.Open();
using var cmd = conn.CreateCommand("CREATE TABLE IF NOT EXISTS table_with_two_fields(id Int32, name String) engine Memory");
await cmd.ExecuteNonQueryAsync();

//generate values
List<int> ids = Enumerable.Range(1, 10_000).ToList();
List<string> names = ids.Select(i => $"Name #{i}").ToList();

//insert data
await using (var writer = await conn.CreateColumnWriterAsync("insert into table_with_two_fields(id, name) values", default))
{
	await writer.WriteTableAsync(new object[] { ids, names }, ids.Count, default);
}

Build requirements

In order to build the driver you need to have .NET SDK 5.0 or higher.