You can create a data flow from one or more data sources. Data flows are a way to produce a curated data source that you can use to easily and efficiently create meaningful visualizations.
The following image shows the Data Flow editor. You use this editor to build your data flow by adding steps and specifying details for those steps. You can select columns, add columns, rename columns, add or adjust aggregates, add filters, add another data set, and add joins. You add steps in the workflow diagram pane and specify details for that step in the workbench pane.
- In the Data Sources page, go to the Create pane and click Data Flow.
- In the Add Data Source dialog, select the data source that you want to base your data flow on. You can select only one data source in this dialog; if needed, you can add additional data sources later. Click Add.The Data Flow editor is displayed and the columns from the selected data source are displayed in the Data Elements pane. The data source name is displayed in the workflow diagram pane.
- In the Data Flow editor, go to the workflow diagram pane and right-click the data source icon. Select Add Step.
- From the Add Step window, click the step that you want to add and provide the required details in the workbench pane. Add as many steps as necessary. Note the following:
- The Data Elements pane is updated based on the step that you’ve selected from the data flow or the step that you’re working on for the data flow. For example, if you add a Select Columns step, remove some columns, and then add an Aggregate step to the data flow, then the Data Elements pane you see while working on the Aggregate step shows the columns that you specified in the previous Select Columns step.
- By default, the workbench pane shows the Step Details view. However, you can click the Preview view option on the workbench pane to see how the data looks with the adjustments that you’re making in the current step.
- Use the Add Data step option to add another data source and join it to the other data sources in your data flow. To create a join, press Ctrl on your keyboard and click the steps that you want to join, right-click, and select Join.
- Oracle Data Visualization validates all of the steps in the data flow as you add them to or delete them from the data flow.
- If you’re adding an expression (in an Add Column step or Filter step), then you must click Apply to finalize the step. If you add a new step to the diagram without clicking Apply, then your expression won’t be applied, and the next step that you add won’t use the correct data.
- You can create filters by adding a filters step and dragging and dropping columns from the Data Elements pane.
- If the data source contains aggregates, then they are displayed when you add an aggregate step. To add a column to the aggregate, hover over the column name, click Actions, and click Aggregate. To remove an aggregate from the selected aggregate list, hover over the aggregate’s name, click Actions, and click Group By.
- Optionally, to delete a step from the workflow diagram, right-click the step and select Delete. Note that deleting a step might make the other steps in the data flow invalid, as indicated by red X icons displayed for the invalid steps.
- When you’ve finished adding steps to the data flow diagram, decide if you want to save the data flow or just execute it without saving it. Note the following options:
- Click Save Data Flow to save but not run the data flow. Note that you can save a data flow that contains validation errors. When you save a data flow, it’s displayed in the Display pane of the Data Sources page, in the Data Flows area.
- If your data flow contains no validation errors, and you’ve added a Save Data step at the end of your data flow, then click Execute data flow. Note that you can’t run a data flow that contains validation errors. After you run the data flow, the resulting data source is displayed in the Display pane of the Data Sources page. Click All Data Sources to see your data source in the list. When you execute a data flow without saving it, the data flow isn’t saved and isn't displayed in the Data Flows list. Therefore, the data flow isn’t available for you to modify or run.