> ## Documentation Index
> Fetch the complete documentation index at: https://docs.e6data.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Delta Lake

> How e6data queries Delta Lake tables through external catalogs, what's supported, and how to connect.

e6data supports querying **Delta Lake** tables through external catalogs such as **AWS Glue**, **Hive Metastore**, **Microsoft Fabric**, and **Unity Catalog**.

<table><thead><tr><th>Capability</th><th>Support</th><th data-hidden="true">Description</th></tr></thead><tbody><tr><td><strong>Deletion vectors</strong></td><td>Supported</td><td>Marks deleted or updated rows without immediately rewriting the underlying Parquet files.</td></tr><tr><td><strong>CHECK constraints</strong></td><td>Supported</td><td>Enforces defined conditions on table data and rejects invalid writes.</td></tr><tr><td><strong>Change Data Feed (CDF)</strong></td><td>Supported</td><td>Captures row-level inserts, updates, and deletes between table versions.</td></tr><tr><td><strong>Generated columns</strong></td><td>Supported</td><td>Automatically calculates column values using expressions based on other columns.</td></tr><tr><td><strong>Column mapping</strong></td><td>Supported</td><td>Allows columns to be renamed or dropped without rewriting existing data files.</td></tr><tr><td><strong>Identity columns</strong></td><td>Supported</td><td>Automatically generates sequential numeric values for inserted rows.</td></tr><tr><td><strong>Row tracking</strong></td><td>Supported</td><td>Assigns stable row identifiers and tracks when each row was last modified.</td></tr><tr><td><strong>Timestamp NTZ</strong></td><td>Supported</td><td>Stores timestamp values without timezone information or timezone conversion.</td></tr><tr><td><strong>Liquid clustering</strong></td><td>Supported</td><td>Organizes data using clustering columns that can evolve as access patterns change.</td></tr><tr><td><strong>Iceberg readers through UniForm</strong></td><td>Supported</td><td>Generates Iceberg-compatible metadata so compatible Iceberg engines can read the Delta table.</td></tr><tr><td><strong>Type widening</strong></td><td>Supported</td><td>Allows compatible changes to wider data types without rewriting existing data files.</td></tr><tr><td><strong><code>VARIANT</code></strong></td><td>Supported</td><td>Stores and queries semi-structured data such as JSON objects, arrays, and scalar values.</td></tr></tbody></table>

## Sample queries

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
-- List all tables in a namespace
SHOW TABLES FROM delta_catalog.analytics;

-- Query from a Delta table
SELECT *
FROM delta_catalog.analytics.user_activity
WHERE event_type = 'purchase';
```

## See also

* [Catalogs overview](/query/catalogs/register-and-manage-catalogs)
* [Iceberg](/query/table-formats/iceberg)


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