Allow AthenaOperator queries without a database argument

[te-horie]

Summary

This PR makes the database argument optional in AthenaOperator, allowing queries that do not require a default database.
This is useful when all referenced table names are fully qualified, such as in queries across multiple databases.

When database is not provided, Database from query_execution_context is used as the fallback database for OpenLineage dataset extraction.

Testing

• ✅ breeze run pytest providers/amazon/tests/unit/amazon/aws/operators/test_athena.py passed (16 test cases).
• ✅ prek run --from-ref upstream/main passed.
• ✅ Successfully ran the system test against Amazon Athena
  1. Locally removed the database argument from the read_table task in example_athena.py like this:

     diff --git a/providers/amazon/tests/system/amazon/aws/example_athena.py b/providers/amazon/tests/system/amazon/aws/example_athena.py
     index 36a37a8e1c..3c72e9b309 100644
     --- a/providers/amazon/tests/system/amazon/aws/example_athena.py
     +++ b/providers/amazon/tests/system/amazon/aws/example_athena.py
     @@ -129,7 +129,6 @@ with DAG(
          read_table = AthenaOperator(
              task_id="read_table",
              query=query_read_table,
     -        database=athena_database,
              output_location=f"s3://{s3_bucket}/",
          )
          # [END howto_operator_athena]

  2. Ran the system test with the following command; it passed ✅:

     $ SYSTEM_TESTS_ENV_ID=airflowtest$(date +%s) breeze run --forward-credentials env AWS_PROFILE=airflow-test pytest --system providers/amazon/tests/system/amazon/aws/example_athena.py
     ...
     providers/amazon/tests/system/amazon/aws/example_athena.py::test_run <- devel-common/src/tests_common/test_utils/system_tests.py PASSED [100%]
     
     ================================================= 1 passed, 1 warning in 56.41s ==================================================

  3. Confirmed that the query succeeded with only Catalog in QueryExecutionContext:

     $ aws athena get-query-execution --query-execution-id <<<REDACTED>>> --profile airflow-test
     QueryExecution:
       ...
       Query: SELECT * from airflowtest1784003174_default.airflowtest1784003174_test_table
       QueryExecutionContext:
         Catalog: awsdatacatalog
       QueryExecutionId: <<<REDACTED>>>
       ...
       Status:
         CompletionDateTime: '2026-07-14T13:27:19.237000+09:00'
         State: SUCCEEDED
         SubmissionDateTime: '2026-07-14T13:27:17.950000+09:00'
       SubstatementType: SELECT
       WorkGroup: primary

---

Was generative AI tooling used to co-author this PR?

• Yes (please specify the tool below)

Generated-by: OpenAI Codex (GPT-5.5) following the guidelines

---

Drafted-by: OpenAI Codex; reviewed by @te-horie before posting

[boring-cyborg]

Congratulations on your first Pull Request and welcome to the Apache Airflow community! If you have any issues or are unsure about any anything please check our Contributors' Guide
Here are some useful points:

• Pay attention to the quality of your code (ruff, mypy and type annotations). Our prek-hooks will help you with that.
• In case of a new feature add useful documentation (in docstrings or in docs/ directory). Adding a new operator? Check this short guide Consider adding an example Dag that shows how users should use it.
• Consider using Breeze environment for testing locally, it's a heavy docker but it ships with a working Airflow and a lot of integrations.
• Be patient and persistent. It might take some time to get a review or get the final approval from Committers.
• Please follow ASF Code of Conduct for all communication including (but not limited to) comments on Pull Requests, Mailing list and Slack.
• Be sure to read the Airflow Coding style.
• Always keep your Pull Requests rebased, otherwise your build might fail due to changes not related to your commits.
  Apache Airflow is a community-driven project and together we are making it better 🚀.
  In case of doubts contact the developers at:
  Mailing List: dev@airflow.apache.org
  Slack: https://s.apache.org/airflow-slack

[Vamsi-klu]

The if self.database: guard in execute() looks right, it skips writing Database into query_execution_context when the arg is unset instead of forcing a None in there, and defaulting the signature to database: str | None = None leaves existing keyword callers alone. Nice that fallback_database = self.database or self.query_execution_context.get("Database") keeps the OpenLineage schema resolution working when the database only arrives through the execution context. One subtle behavior maybe worth a docstring line: with database=None and a query_execution_context that already sets Database, execute() now preserves that value instead of overwriting it, which looks like the right call but is easy to miss. The two new tests cover the no database run and the context fallback, so this looks good to me.

[te-horie]

One subtle behavior maybe worth a docstring line: with database=None and a query_execution_context that already sets Database, execute() now preserves that value instead of overwriting it, which looks like the right call but is easy to miss.

Thank you for your suggestion!
I added a note to the database parameter docstring in f72d787 explaining that any Database value in query_execution_context is used when database is omitted or set to None.

[boring-cyborg]

Awesome work, congrats on your first merged pull request! You are invited to check our Issue Tracker for additional contributions.