KNIME is a great tool for building analytical workflows. Creating a workflow using KNIME involves dragging and dropping built-in nodes into a canvas. There is a privilege to extend KNIME by adding nodes developed by the KNIME community or adding your nodes. The creation of workflows is very fast and user-friendly with KNIME.
The KNIME workflows, node settings, and data produced by the workflow are all stored in the KNIME workspace in a folder on your PC. The workflows and data stored in the workspace are accessible through the KNIME Explorer in the upper left corner of the KNIME Workbench.
Must Check: Basics of Nodes & Workflow in KNIME
Build Your First KNIME Workflow
In the KNIME Analytics Platform, individual tasks are denoted by nodes. Each node is presented as a colored box with input and output ports, as well as a status. Nodes can perform all kinds of tasks, like reading/writing files, transforming data, training models, creating visualizations, etc. A collection of interrelated nodes creates a workflow, and usually represents some part or perhaps all of a particular data analysis project.
Let’s now see how to build a workflow in KNIME using a data file. When we’re done, it will look like the workflow.
Must Check: Features of KNIME Analytics Platform
Step By Step Build KNIME Workflow
- To get started, you should have the data file with you to use in the workflow.
- Then, create a new blank workflow by:
- Clicking on the option “New” in the toolbar panel at the top of the KNIME Workbench
- Or by right-clicking on a folder of local workspace in the KNIME Explorer.
- The first node you require is the File Reader node, which you will get in the node repository. You can either navigate to IO → Read → File Reader or just type a part of the name in the search box in the node repository panel.
- To use the node in your workflow you can either:
- Just drag and drop the node from the node repository into the workflow editor
- Or double click on the node in the node repository. It will automatically get added in the workflow edit.
- Let’s now define the settings for this node:
- Open the configuration dialog either by directly double-clicking on the File Reader node or by right-clicking it and selecting the “Configure” option.
- In the configuration dialog, define the file path by clicking the “Browse” button, then check other available settings, and preview the data.
- Now you need to inspect the output table to make sure if the data file was read as you intended. To inspect the output table:
- Execute the File Reader node by right-clicking on a node and selecting “Execute” option
- Once the node gets executed, open the output table by right-clicking on the executed node and selecting the “File Table” option from the menu
- If the data was read incorrectly, add the Column Filter node to the workflow editor and connect it to the File Reader node:
- Click on the output port of the File Reader node by pressing the mouse button and releasing it at the input port of the Column Filter node
- Otherwise, select the File Reader node by clicking it once in your workflow and then double-clicking the Column Filter node in the node repository. This will automatically connect the Column Filter node to the File Reader node.
- Before you proceed, you must configure the Column filter node:
- Move the columns into the green-framed Includefield either by double-clicking them or using the buttons between the Exclude and Include fields in the configuration dialog
- Click on OK to complete the configuration
- Continue building the workflow:
- After connecting the column filter row, now add the Row Filter node to the workflow editor and connect it to the Column Filter node
- Open the configuration dialog of the Row Filter node and exclude rows from the input table where the column values are unknown
- Now that the data has been filtered, let’s move on to data visualization:
- Search for the nodes Stacked Area Chart and Pie/Donut Chart in the node repository, and add them to the workflow editor, both connected to the Row Filter node
- Open the configuration dialog of the Stacked Area Chart node. Select the columns for a stacked area chart.
- Then open the configuration dialog of the Pie/Donut Chart node and select the columns for the pie chart.
- The workflow is finished, and the next step is to execute it and view the output. You do this either by clicking on the “Execute all executable nodes” button in the toolbar or by selecting the last nodes of the different branches of the workflow, right-clicking the selection, and then click “Execute” button in the menu.
- Choose the “Execute and Open Views” option for an unexecuted node
- Or, right-click the node and select “Interactive View” option once the node gets executed
- Currently, the pie chart uses default colors to show different elements of the data. With the Color Manager node, you can assign different colors for different parameters than the default ones. The colors have to be assigned before adding the graph, so you’ll have to add the Color Manager node in between the workflow.
- Add the Color Manager node:
- You can add the color management node by dragging the node from the node repository and releasing it on its place between the Row Filter node and the Pie Chart node in the workflow when the connection turns out red. The red connection indicates that it is ready to accept the new node when you release the mouse click.
If you want to learn more, then check out our KNIME Crash Course to build high-quality and interactive KNIME Workflow to analyze any type of data. This certification training will offer you high-quality videos with 24 x 7 online support.