This is the implementation of the ClickHouse data handler for MindsDB. ClickHouse is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).

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Implementation

This handler was implemented using the standard clickhouse-sqlalchemy library. The required arguments to establish a connection are as follows:
  • host is the hostname or IP address of the ClickHouse server.
  • port is the TCP/IP port of the ClickHouse server.
  • user is the username used to authenticate with the ClickHouse server.
  • password is the password to authenticate the user with the ClickHouse server.
  • database defaults to default. It is the database name to use when connecting with the ClickHouse server.
  • protocol defaults to native. It is an optional parameter. Its supported values are http and https.
If you installed MindsDB locally via pip, you need to install all handler dependencies manually. To do so, go to the handler’s folder (mindsdb/integrations/handlers/clickhouse_handler) and run this command: pip install -r requirements.txt.

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Usage

In order to make use of this handler and connect to the ClickHouse database in MindsDB, the following syntax can be used: 
CREATE DATABASE clickhouse_datasource
WITH
    engine = 'clickhouse',
    parameters = {
      "host": "127.0.0.1",
      "port": "9000",
      "user": "root",
      "password": "password",
      "database": "test_db"
    };
You can use this established connection to query your table as follows: 
SELECT *
FROM clickhouse_datasource.example_table;
If you want to switch to a different database instead of the one you have connected, you can include it in the query as:
SELECT *
FROM clickhouse_datasource.new_database.example_table;