AshClickhouse

Note: This library is under active development, unstable and the API may change.

An Ash Framework data layer for ClickHouse. It implements the Ash.DataLayer behaviour using the clickhouse client.

Features

ClickHouse is a full SQL columnar store, so most Ash query features map directly:

• CRUD (create, read, update, destroy)
• filter, sort, limit, offset, select, distinct
• bulk_create (batch INSERT)
• update_query / destroy_query (via ALTER TABLE ... UPDATE/DELETE)
• Native aggregates (count, sum, avg, min, max)
• multitenancy (database- or attribute-based)
• calculate, composite_primary_key, nested_expressions, boolean_filter
• join, combine (UNION/INTERSECT), filter_relationship, exists, aggregate_relationship

Not supported

• transact / lock — ClickHouse has no multi-statement transactions
• keyset — ClickHouse has no token-based keyset pagination (use offset)
• upsert — ClickHouse has no ON CONFLICT (use create + update_query)

Installation

def deps do
  [
    {:ash_clickhouse, "~> 0.1.0"}
  ]
end

Quick start

1. Configure a Repo

defmodule MyApp.Repo do
  use AshClickhouse.Repo, otp_app: :my_app
end

# config/config.exs
config :my_app, MyApp.Repo,
  url: "http://localhost:8123",
  database: "my_app_dev"

2. Add to your supervision tree

children = [MyApp.Repo, ...]

3. Define a resource

defmodule MyApp.User do
  use Ash.Resource,
    data_layer: AshClickhouse.DataLayer,
    domain: MyApp.Domain

  clickhouse do
    table "users"
    repo MyApp.Repo
    engine "MergeTree()"
    order_by "id"
  end

  attributes do
    uuid_primary_key :id
    attribute :name, :string
    attribute :email, :string
  end

  actions do
    defaults [:create, :read, :update, :destroy]
  end
end

4. Create the database and tables

mix ash_clickhouse.setup
mix ash_clickhouse.migrate

5. Use it

{:ok, user} = Ash.create(MyApp.User, %{name: "John", email: "john@example.com"})
users = Ash.read!(MyApp.User)

Configuration

Resource (clickhouse DSL)

Repo

License

Apache-2.0. See LICENSE.