# DuckDB

Soda supports DuckDB as a flexible, lightweight SQL engine that can be used with native `.duckdb` files, in-memory data, or external dataframes such as Pandas and Polars.

### Connection configuration reference

Install the following package:

```bash
pip install soda-duckdb
```

#### Data source YAML

**Create the config file:**

```shellscript
soda data-source create -f ds_config.yml
```

The data source configuration YAML should look like the following:

{% code title="ds\_config.yml" %}

```yaml
type: duckdb 
name: my_duckdb
connection: 
    database: "adventureworks.duckdb" # or a supported file path like "dim_employee.parquet"
```

{% endcode %}

#### Contract YAML

{% code title="contract.yml" %}

```yaml
dataset: datasource/main/adventureworks

columns:
  - name: id
    checks:
      - missing:
  - name: name
    checks:
      - missing:
          threshold:
            metric: percent
            must_be_less_than: 10
  - name: size
    checks:
      - invalid:
          valid_values: ['S', 'M', 'L']

checks:
  - schema:
  - row_count:
```

{% endcode %}

***

DuckDB also supports registering **in-memory data frames** from **Pandas** or **Polars,** and creating **temporary tables for contract testing**. You can run Soda contracts against these datasets by passing the live DuckDB cursor to `DuckDBDataSource.from_existing_cursor` as described in the following page:

> Learn more: [duckdb-advanced-usage](https://docs.soda.io/reference/data-source-reference-for-soda-core/duckdb/duckdb-advanced-usage "mention")

### Connecting to MotherDuck

You can also connect Soda to **MotherDuck** using the same DuckDB package. MotherDuck is a managed cloud service for DuckDB that provides persistent storage and database sharing while preserving DuckDB’s execution model. To connect, use the `md:` connection string and provide a MotherDuck service token via an environment variable.

```yaml
name: my_duckdb
connection:
  database: "md:my_db?motherduck_token=${env.MDTOKEN}"
```

Soda uses DuckDB’s native MotherDuck integration, so no additional drivers or configuration are required. The specified database is created automatically if it does not already exist. Ensure the `MDTOKEN` environment variable is set before running Soda.

<br>

***

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