RepoDb.ClickHouse.BulkOperations 1.17.0-alpha1

<div align="center"> <a href="https://repodb.net/tutorial/get-started-clickhouse/"><image src="ClickHouse.png" style="width:256px;" /></a> <br/> <span style="font-size:28px;font-weight:bold;"><a href="https://repodb.net/tutorial/get-started-clickhouse/"><strong>RepoDb.ClickHouse.BulkOperations</strong></a></span> <br/> <span style="font-size:16px;">A high-performance data productivity platform for bulk operations on ClickHouse in .NET.</span> </div>

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RepoDb.ClickHouse.BulkOperations

A high-performant extension library of RepoDB that does bulk operations towards a ClickHouse database. It uses its own internal class ClickHouseBulkCopy to load the data towards the database, built on top of ClickHouse.Driver's native ClickHouseBulkCopy streaming-insert implementation.

Important Pages

• GitHub Home — core library and source code.
• Website — full documentation, API reference, and blog.

Core Features

• Async Methods
• BulkInsert
• BulkMerge
• BulkUpdate
• BulkDelete
• BulkDeleteByKey
• Column Mappings Behavior

Community

• GitHub Issues — bug reports and feature requests.
• Microsoft Teams — live Q&A.
• GitHub Discussions — ask questions and share ideas.
• X / Twitter — news and updates.

License

Apache-2.0 — Copyright © 2026 Michael Camara Pendon

Installation

Install-Package RepoDb.ClickHouse.BulkOperations

Then call the setup for ClickHouse.

RepoDb
    .Setup()
    .UseClickHouse();

Waiting for mutations: BulkMerge/BulkUpdate/BulkDelete/BulkDeleteByKey all resolve to ClickHouse's asynchronous ALTER TABLE ... UPDATE/DELETE mutations under the hood, applied by a background merge rather than immediately - a query issued right after one of these calls returns is not guaranteed to see the change yet. Pass isWaitForMutationsEnabled: true to UseClickHouse() (it defaults to false) to have these operations block until each mutation actually finishes (up to a 5-second timeout) before returning, trading extra latency per call for read-your-writes consistency. This is read from ClickHouseDbSetting.IsWaitForMutationsEnabled on the mapped IDbSetting - see the RepoDb.ClickHouse README for details.

Async Methods

Every synchronous operation has a corresponding Async overload.

BulkInsert

Inserts a list of entities into the database in bulk. Returns the number of inserted rows.

using (var connection = new ClickHouseConnection(ConnectionString))
{
    var customers = GetCustomers();
    var insertedRows = connection.BulkInsert<Customer>(customers);
}

Or via table-name:

using (var connection = new ClickHouseConnection(ConnectionString))
{
    var customers = GetCustomers();
    var insertedRows = connection.BulkInsert("Customer", customers);
}

Or via a DataTable:

using (var connection = new ClickHouseConnection(ConnectionString))
{
    var table = GetCustomersAsDataTable();
    var insertedRows = connection.BulkInsert("Customer", table);
}

Note: Unlike the SQL Server/MySQL/Oracle providers, ClickHouse has no identity, auto-increment, or sequence mechanism of any kind, so ClickHouseBulkImportIdentityBehavior.ReturnIdentity is not supported here - passing it throws a NotSupportedException. Use KeepIdentity (the default) instead, and assign your own key values before inserting.

BulkMerge

Upserts a list of entities in bulk — inserts new rows and updates existing ones based on the defined qualifiers. Returns the number of affected rows.

using (var connection = new ClickHouseConnection(ConnectionString))
{
    var customers = GetCustomers();
    var mergedRows = connection.BulkMerge<Customer>(customers);
}

Or with qualifiers:

using (var connection = new ClickHouseConnection(ConnectionString))
{
    var customers = GetCustomers();
    var mergedRows = connection.BulkMerge<Customer>(customers, qualifiers: e => new { e.LastName, e.DateOfBirth });
}

Or via table-name with qualifiers:

using (var connection = new ClickHouseConnection(ConnectionString))
{
    var customers = GetCustomers();
    var mergedRows = connection.BulkMerge("Customer", customers, qualifiers: Field.From("LastName", "DateOfBirth"));
}

Or via a DataTable:

using (var connection = new ClickHouseConnection(ConnectionString))
{
    var table = GetCustomersAsDataTable();
    var mergedRows = connection.BulkMerge("Customer", table);
}

BulkUpdate

Updates existing rows in the database in bulk, matched by the defined qualifiers. Returns the number of updated rows.

using (var connection = new ClickHouseConnection(ConnectionString))
{
    var customers = GetCustomers();
    var rows = connection.BulkUpdate<Customer>(customers);
}

Or with qualifiers:

using (var connection = new ClickHouseConnection(ConnectionString))
{
    var customers = GetCustomers();
    var rows = connection.BulkUpdate<Customer>(customers, qualifiers: e => new { e.LastName, e.DateOfBirth });
}

Or via a DataTable:

using (var connection = new ClickHouseConnection(ConnectionString))
{
    var table = GetCustomersAsDataTable();
    var rows = connection.BulkUpdate("Customer", table);
}

BulkDelete

Deletes existing rows from the database in bulk, matched by the defined qualifiers. Returns the number of deleted rows.

using (var connection = new ClickHouseConnection(ConnectionString))
{
    var customers = GetCustomers();
    var deletedRows = connection.BulkDelete<Customer>(customers);
}

Or with qualifiers:

using (var connection = new ClickHouseConnection(ConnectionString))
{
    var customers = GetCustomers();
    var deletedRows = connection.BulkDelete<Customer>(customers, qualifiers: e => new { e.LastName, e.DateOfBirth });
}

Or via a DataTable:

using (var connection = new ClickHouseConnection(ConnectionString))
{
    var table = GetCustomersAsDataTable();
    var deletedRows = connection.BulkDelete("Customer", table);
}

BulkDeleteByKey

Deletes existing rows from the database in bulk, matched by their primary (or identity) key value alone — no entities or DataTable involved, just the list of key values to remove. Returns the number of deleted rows.

using (var connection = new ClickHouseConnection(ConnectionString))
{
    var primaryKeys = new [] { 10045, 10046, 10047 };
    var deletedRows = connection.BulkDeleteByKey("Customer", primaryKeys);
}

Column Mappings Behavior

When no mappings are passed to BulkInsert, BulkMerge, or BulkUpdate (or their async variants), and for BulkDelete (which has no mappings argument), the columns of the source (entities, DataTable, or DbDataReader) are aligned with the columns of the destination table based on the BulkColumnMappingsBehavior setting:

Automatic is the default and is the behavior of the earlier versions. The setting is a property of the ClickHouseBulkDbSetting (which inherits ClickHouseDbSetting), and UseClickHouse(...) registers it as the setting of the connection in place of the default one. Strict and StrictBypass throw a ClickHouseBulkColumnMappingsException (naming the offending columns) before any data is written.

GlobalConfiguration
    .Setup()
    .UseClickHouse(new ClickHouseBulkDbSetting
    {
        BulkColumnMappingsBehavior = ClickHouseBulkColumnMappingsBehavior.StrictBypass
    });

For example, with a Customer table that has the Id, Name, Email, and CreatedDateUtc columns, and a list of entities (the source) with the Email, Name, and Nickname properties:

• Strict throws, because the order differs, Id/CreatedDateUtc are missing, and Nickname does not exist in the destination.
• StrictBypass throws, because Nickname does not exist in the destination.
• Automatic inserts Name and Email, and ignores Nickname.

try
{
    await connection.BulkInsertAsync("Customer", customers);
}
catch (ClickHouseBulkColumnMappingsException ex)
{
    // e.g. "... Source column(s) that do not exist on the destination table: 'Nickname'."
    logger.LogError(ex, "Bulk insert rejected due to column misalignment.");
    throw;
}

Explicitly passed mappings always take precedence: the setting is not applied to them. BulkDeleteByKey is not affected, as its source is a list of key values rather than a set of columns.

License

Apache License 2.0 — Copyright © 2026 Michael Camara Pendon

This project depends on ClickHouse.Driver (the ADO.NET driver for ClickHouse, formerly known as ClickHouse.Client), which is separately licensed under the MIT License.