Description:
This step evaluates the column expression during the ETL transformation process.
Inputs
- transforms – Configure transform list
Returns
- None
Usage:
Prerequisite:
The ETL process engine service should be running to execute the ETL definitions.
Example:
Let’s build and execute the “clsComputeExpressionDef” example.
- Create a new ETL definition named “clsComputeExpressionDef” and open it in designer mode.
- Drag “clsInputCSV, clsComputeExpression, and clsOutputCSV” steps to the canvas.
- Connect the dots between the “clsInputCSV” step and other steps, as shown above.
- Define a variable or a global to hold the file path.
- Click the "clsInputCSV" step to configure its "Required" properties. Enter a name for the step. Enter the path to the input CSV file on the application server. Select the ETL data schema from the drop-down list. Note: The schema's column names should match those in the input file. Click the Save button.
- Click the "clsInputCSV" step to view its "Optional" properties. Select the Show Schema button. The pop-up window displays the schema columns as shown below. This function helps to understand the schema at a glance.
- Click the "clsComputeExpression" step to configure its "Required" properties. Provide a name for the step. Click the button to configure the transform list, then click Save.
- Click the "clsComputeExpression" step to configure the transform list. A pop-up window will appear. Click the Add Row (+) button to insert an empty row. Enter the expression to evaluate. Click the Save button. You may add multiple transformation columns by using the Add Row button.
- Click the "clsOutputCSV" step to configure its "Required" properties. Enter a name for the step. Enter the path to the output CSV file on the application server. Click the Save button.
- Click the "clsOutputCSV" step to configure its "Optional" properties. Provide a name for the step. Provide a variable or global reference to store the virtual output path. Click the Save button.
- The “Logging” configuration is necessary for documentation and also measures workflow progress and percent complete. This is achieved by configuring the step state and percent fields individually, as shown in the images below. Configure the “Logging” using the following properties.
- Save the ETL definition, create a new ETL instance, and execute. Render the ETL instance. Click the ETL step to view its properties. The “clsComputeExpression” step should transform the output file by evaluating the expression result. The variable or global reference contains the output file’s virtual path, as shown below.
Definition Sample:
You may download the sample definition(s) from the link provided and later import them (drag-and-drop) into your FlowWright ETL Process Definition (XML file) page.
Note: Please verify and complete the import process steps for any missing configurations, such as file path references and database connections. Then, save the definition to confirm the changes.