Create an SQL application
============================

In Aiven for Apache Flink®, you can create an SQL application that uses Apache Flink SQL to streamline the process of building data processing pipelines. The SQL application simplifies the process of defining source and sink tables, implementing data processing logic, and managing application deployment.

Prerequisite
------------
Before creating applications, configure the :doc:`data service integration </docs/products/flink/howto/create-integration>` for seamless integration and data management within your Flink applications.

Create and deploy application
-------------------------------

Create an SQL application in Aiven for Apache Flink® using the `Aiven Console <https://console.aiven.io/>`_:

1. In the `Aiven Console <https://console.aiven.io/>`_, select the Aiven for Apache Flink service where you want to create and deploy a Flink application.
2. From the left sidebar, click **Applications** and then click **Create application**.
3. In the **Create application** dialog, enter the name of your application and select **SQL** as the application type. 
4. Click **Create application**.
5. Click **Create first version** to create the first version of the application. 
6. Click **Add your first source table** to add a source table. 
   
   .. note::
      As this is your first application, no other applications are available to import source tables.

7. On the **Add new source table** screen:
    
   * Use the **Integrated service** drop-down to select the service.
   * In the **Table SQL** section, enter the SQL statement to create the source table.
   * Optionally, click **Run** to test how data is being retrieved from the data source. This may vary in time based on the data volume and connection speed.
   * Click **Add table**.
8. Click **Next** to proceed to adding a sink table and click **Add your first sink table**.
   
   .. note::   
      As this is your first application, no other applications are available to import sink tables.
    
9. On the **Add new sink table** screen:
    
   * Use the **Integrated service** drop-down to select the service.
   * In the **Table SQL** section, enter the SQL statement to create the sink table.
   * Click **Add table**.
10. Click **Next** to enter the **SQL statement** that transforms the data from the source stream. Optionally, click **Run** to see how the data is extracted from the source.

11. Click **Save and deploy later** to save the application. You can view and access the application you created on the application overview page. 

    .. image:: /images/products/flink/application_landingpage_view.png
        :scale: 50 %
        :alt: Application landing page with a view of the source table, SQL statement, and sink table
    
12. To deploy the application, click **Create deployment**. In the **Create new deployment** dialog:
    
    * Select the application version to deploy. The default version for the first deployment is **Version: 1**.
    * Select a :doc:`savepoint </docs/products/flink/concepts/savepoints>` if you wish to deploy from a specific state. No savepoints are available for the first application deployment. 
    * Toggle **Restart on failure** to automatically restart Flink jobs upon failure.
    * Specify the number of `parallel instances <https://nightlies.apache.org/flink/flink-docs-master/docs/dev/datastream/execution/parallel/>`_ you require for the task.
13. Click **Deploy without a savepoint** to begin the deployment process.
14. While deploying, the application status shows **Initializing**. Once deployed, the status changes to **Running**.

Create SQL applications using Aiven CLI
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For information on creating and managing Aiven for Apache Flink application using :doc:`Aiven CLI </docs/tools/cli>`, see :doc:`Manage Aiven for Apache Flink® applications </docs/tools/cli/service/flink>` document.