-`url` — Bucket url with the path to an existing Iceberg table in S3.
-`aws_access_key_id`, `aws_secret_access_key` - Long-term credentials for the [AWS](https://aws.amazon.com/) account user. You can use these to authenticate your requests. These parameters are optional. If credentials are not specified, they are used from the ClickHouse configuration. For more information see [Using S3 for Data Storage](/docs/en/engines/table-engines/mergetree-family/mergetree.md/#table_engine-mergetree-s3).
-`format` — The [format](/docs/en/interfaces/formats.md/#formats) of the file. By default `Parquet` is used.
-`structure` — Structure of the table. Format `'column1_name column1_type, column2_name column2_type, ...'`.
ClickHouse currently supports reading v1 (v2 support is coming soon!) of the Iceberg format via the `iceberg` table function and `Iceberg` table engine.
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## Defining a named collection
Here is an example of configuring a named collection for storing the URL and credentials: