Basics of Nodes and Workflow in KNIME | KNIME Tutorials

KNIME is one of the best analytics platforms. The knowledge of the KNIME Analytics Platform store in the Node Repository. So before Leaning the KNIME, you should first understand What is Nodes? and What are Workflows in KNINE? This gives you a good glimpse of the KNIME Analytics Platform. If you want to know more then kindly check our KNIME Analytics Course. Before moving further you have to download & install KNIME in your Windows or Mac.

Nodes and Workflows in KNIME

In the KNIME Analytics Platform, individual tasks are represented by nodes. Each node is displayed as a colored box with input and output ports, as well as a status. The inputs are the data that the node processes and the outputs are the resulting datasets.

Each node has definite settings, which we can monitor in a configuration dialog. When we change the settings, the node status changes, and it is indicated by a traffic light below each node. Nodes can perform all sorts of tasks, including reading and writing files, transforming data, training models, creating visualizations, and so on.

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What is KNIME Workflow?

KNIME workflow can be used as a data set to create a report template that can be exported to document formats like doc, ppt, xls, pdf, and others. The KNIME workspace is a folder on your local computer to store your KNIME workflows, node settings, and data produced by the workflow. The workflows and data stored in your workspace are accessible through the KNIME Explorer in the upper left corner of the KNIME Workbench.

Must Check: Importance of KNIME

Creating a New KNIME Workflow

  • When we start the KNIME Analytics Platform, after the splash screen, you are asked for the path to the workspace where all your work is stored. Browse to an existing folder, or create a new one, or just accept the default workspace in this text box.
  • If you don’t want to ever be asked again for the workspace path, enable the flag and click “OK”.
  • Once inside the KNIME Analytics Platform, you can always change the workspace through “File” and then “Switch Workspace”, and then you select the new workspace folder.
  • Now you need to start a new workflow by right-clicking the local workspace and selecting “New KNIME Workflow” or “New Workflow Group”, depending on what is to be created.
  • You have to first create a new workflow group. Name the new workflow group and give it a destination inside the local workspace in the KNIME Explorer.
  • We can use the “Browse” button to select the folder in the local workspace to create the new workflow. The newly created workflow is initially blank.

Now you can start creating your first KNIME Workflow.

What is KNIME Node?

A node is a minute programming unit in KNIME. Each node performs a dedicated task, from simple to complicated ones like changing the name of a data column to train a random forest. When a node is created, it requires the settings to execute the task. This phase is called configuration. After configuration, a node needs to be implemented to essentially carry out the assigned task.

How to Create and Execute a Node?

  • To create a node, just drag and drop the node from the Node Repository into the Workflow Editor or double click the node in the node repository. This automatically creates a node in the workflow editor.
  • Two nodes can be connected to each other by clicking at the output port of the first node and releasing it at the input port of the second node.
  • A connection between two nodes means that the output data of the first node are used as input by the second node.
  • If you select a node in the workflow editor and double click a node in the node repository, the node is created and automatically connected to the node that was selected in the workflow editor.
  • Every node that has been newly created has a red-light status. It needs configuration to execute its task.
  • To open the configuration window, you have to double click on a node or right-click the node, and then select the “Configure” option.
  • The configuration window of a node contains the required settings for the node to execute its task.
  • Right-clicking a node brings up its context menu. The context menu contains several commands for the selected node.
  • If the execution is successful, the node status gets the green light. Actually, it undoes the node execution.
  • The last option in the context menu always brings up the data at the output port.
  • Nodes can have one or more input ports or zero input ports, and they can have one or more or zero output ports, depending on how many datasets they need as input and produce as output.
  • Node’s context menu contains several commands among which the most basic ones are “Configure”, “Reset”, “Execute” and the last option to visualize the output data.
  • Another way to execute a selected node or a group of selected nodes is to click the green button with a single arrow.
  • If we reset the first node, the old workflow gets reset, and to re-execute all nodes in an executable status, we have to click the green button with the double arrow. This button executes all nodes that are in an executable status, so all nodes with a yellow light.

Therefore, we have seen here how to create, configure, execute, reset a node, and how to inspect the results that have been created by a node.

Must Check: Features of KNIME Analytics Platform

Conclusion

In this blog we learned that collection of interconnected nodes constitutes a workflow, and usually represents some part or perhaps all of a particular data analysis project.

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Data in the KNIME Analytics Platform is stored in the Node Repository. The Node Repository is divided into sections, each one assigned to a special task like data access, data manipulation, data analytics, and so on.

When you are creating your workflow step by step and you are not sure what your next step will be, the Workflow Coach can guide with valid help. If you are looking to learn more, then check out our latest KNIME Traning Program and become an expert in KNIME.