Export: SQL

Converts a data contract into a SQL data definition language (DDL) file.

datacontract export sql datacontract.yaml --output output.sql

The SQL dialect is determined from the servers block in the data contract (e.g. type: postgres, type: snowflake). Alternatively, pass it explicitly:

datacontract export sql datacontract.yaml --dialect postgres --output output.sql

Supported dialects: postgres, mysql, snowflake, databricks, sqlserver, trino, oracle, clickhouse (and auto, the default, which detects the dialect from the server type).

:::note Databricks variant columns If an error is thrown when deploying SQL DDLs with variant columns on Databricks, set:

spark.conf.set("spark.databricks.delta.schema.typeCheck.enabled", "false")

:::

ClickHouse

datacontract export sql datacontract.yaml --dialect clickhouse --output ddl.sql

ClickHouse requires a table engine (default ENGINE = MergeTree()) and uses ORDER BY as its primary key mechanism. Primary key fields in the contract are translated to the ORDER BY clause.

# Custom engine
datacontract export sql datacontract.yaml --dialect clickhouse \
  --clickhouse-engine "ReplicatedMergeTree('/clickhouse/tables/{shard}/table', '{replica}')"

# Custom ORDER BY (defaults to primary key columns if defined)
datacontract export sql datacontract.yaml --dialect clickhouse \
  --clickhouse-order-by "event_date DESC, event_id"

Option	Description
`--clickhouse-engine`	The table engine. Default: `MergeTree()`.
`--clickhouse-order-by`	Comma-separated `ORDER BY` columns. Defaults to primary key columns.

Override any field's ClickHouse type individually by setting the custom property clickhouseType in the data contract.

ClickHouse​

ClickHouse