## What column keys does Atlan crawl?

URL: https://docs.atlan.com/product/connections/faq/column-keys-crawled

> Learn about what column keys does atlan crawl?.

If the following column keys are defined in the SQL database at source, Atlan can crawl and display them as attributes for your assets:

- **Primary key** - uniquely identifies each row in a table.
- **Foreign key** - links together two tables.
- **Partition key** - determines logical partitions in a table.
- **Sort key** - determines the order in which rows are stored in a table.
- **Index key** - defines the order for an index in the database.
- **Cluster key** - determines the order in which the database is partitioned.
- **Distributed key** - determines where data is stored in a database.

## View column keys

Navigate to the left menu of any screen in Atlan and click on **all assets** to begin:

(If you are using the **Old UI (Classic)**, click **Assets** instead.)

### From the asset preview

To view column keys in the asset preview:

- From the _Assets_ page, navigate to the asset preview section. The asset preview for column assets displays available column keys.

### From the asset profile

To view column keys in the asset profile:

1. From the _Assets_ page, right-click a table or a column asset and select **Open profile**.
2. Navigate to _Column preview_ to view available column keys.

### From the sidebar

To view column keys in the sidebar:

1. From the _Assets_ page, click a table or a column asset.
2. In the sidebar to the right, click the **Columns** tab to view available column keys in the sidebar.

## Create foreign key relationships

You can create foreign key relationships only through APIs for column assets in Atlan. You can use the `foreignKeyTo` and `foreignKeyFrom` statements to create column references for foreign keys and maintain the referential integrity of the assets. Refer to the [developer documentation](https://docs.atlan.com/llms/platform/types/column/llms.txt) to assign foreign key relationships.

Once you have created foreign key relationships, users can view the column references and better understand the relationships between assets.

## Filter assets by column keys

You can filter asset search results by [type-specific property](https://docs.atlan.com/llms/catalog/discovery/use-the-filters-menu/llms.txt) filters, such as column keys for column assets. 

To filter column assets by column keys:

1. From the left menu of any screen in Atlan, click on **all assets**.

 If you are using the **Old UI (Classic)**, from the left menu of any screen in Atlan, click **Assets**.

2. Under the search bar on the _Assets_ page, click the **Column** tab to filter for column assets.
3. In the _Filters_ menu on the left, click the **Column** filter.
4. To add a [type-specific property](https://docs.atlan.com/llms/catalog/discovery/use-the-filters-menu/llms.txt) filter to refine the search, select a column-type property filter - for example, _Primary key_.
5. In the filter dialog, click **Yes** to view column assets with a primary key or click **No** to only view column assets without a primary key.

## Supported sources

Atlan supports column keys for the following connectors:

- [Amazon Athena](https://docs.atlan.com/llms/connectors/amazon-athena/what-does-atlan-crawl-from-amazon-athena/llms.txt)
- [Amazon Redshift](https://docs.atlan.com/llms/connectors/amazon-redshift/what-does-atlan-crawl-from-amazon-redshift/llms.txt)
- [AWS Glue](https://docs.atlan.com/llms/connectors/aws-glue/what-does-atlan-crawl-from-aws-glue/llms.txt)
- [Databricks](https://docs.atlan.com/llms/connectors/databricks/what-does-atlan-crawl-from-databricks/llms.txt)
- [Google BigQuery](https://docs.atlan.com/llms/connectors/google-bigquery/what-does-atlan-crawl-from-google-bigquery/llms.txt)
- [Hive](https://docs.atlan.com/llms/connectors/hive/what-does-atlan-crawl-from-hive/llms.txt)
- [Microsoft Azure Synapse Analytics](https://docs.atlan.com/llms/connectors/microsoft-azure-synapse-analytics/what-does-atlan-crawl-from-microsoft-azure-synapse-analytics/llms.txt)
- [Microsoft SQL Server](https://docs.atlan.com/llms/connectors/microsoft-sql-server/what-does-atlan-crawl-from-microsoft-sql-server/llms.txt)
- [MySQL](https://docs.atlan.com/llms/connectors/mysql/what-does-atlan-crawl-from-mysql/llms.txt)
- [Oracle](https://docs.atlan.com/llms/connectors/oracle/what-does-atlan-crawl-from-oracle/llms.txt)
- [PostgreSQL](https://docs.atlan.com/llms/connectors/postgresql/what-does-atlan-crawl-from-postgresql/llms.txt)
- [SAP HANA](https://docs.atlan.com/llms/connectors/sap-hana/what-does-atlan-crawl-from-sap-hana/llms.txt)
- [Snowflake](https://docs.atlan.com/llms/connectors/snowflake/what-does-atlan-crawl-from-snowflake/llms.txt)
- [Teradata](https://docs.atlan.com/llms/connectors/teradata/what-does-atlan-crawl-from-teradata/llms.txt)

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