Import: ClickHouse

Creates a data contract from a ClickHouse database by reading system.tables and system.columns — including the full declared column types, the sorting key, and the comments on tables and columns.

datacontract import clickhouse \
  --source localhost \
  --database sales \
  --output datacontract.yaml

--source is the host of your ClickHouse server. Add --port if its HTTP interface doesn't listen on the default 8123, and repeat --table to import only specific tables (by default every table and view in the database is imported).

ClickHouse reports a complete type string, so Nullable(String), LowCardinality(String) and Decimal(10, 2) are taken verbatim and match what datacontract test reads back. A column is required unless its type is Nullable, and the columns of the sorting key become the primary key.

The generated contract includes a ready-to-test servers block, so you can run datacontract test datacontract.yaml immediately afterwards — see the ClickHouse connection guide for the full 5-minute walkthrough and troubleshooting.

Credentials are the same ones datacontract test uses — see the ClickHouse Reference.

Only have a DDL file? Use datacontract import sql --dialect clickhouse.

All options: datacontract import clickhouse.