Getting Started Guide

To get started, first download the xls file that contains the data that you are going to use in the workflow. Open your KNIME Analytics Platform and create a new, empty workflow by clicking the yellow "plus" button on the entry page.

From the download folder, drag and drop the xls-file into the workflow editor. An Excel Reader node will appear on the canvas. The node is already configured with the default settings. To open the configuration dialog of the node and inspect the settings, click the configuration cog button in the node action bar.

Here you can see the path to the file you dropped into the workflow editor and a preview of the data table. You can also select the sheet that you want to read the data from. First, read the data in the Kitchen sheet. Click OK and execute the Excel Reader node by clicking the execute play button in the node action bar. Now the input data are available at the output port of the Excel Reader node. You can view the output table when you select the node in the node monitor, at the bottom of the workbench.

Next, drag and drop a second Excel Reader node from the node repository and configure it in such a way that it reads the same xls file but, this time, read in the data from the sheet called Living room.

The data in the second sheet needs to be cleaned. In fact, they contain a column named Comment that we want to filter out. 

To do so, search, drag, and drop the Column Filter node from the node repository into the workflow editor. Then connect its input port with the output port of the second Excel Reader node.
Open the configuration dialog of the node by clicking the configuration cog button in the node action bar.
Here, move the column Comment into the Excludes field by first selecting it from the list and then clicking the single arrow pointing to the left. Click OK, and Execute the node. Now the filtered data table is available at the output port of the Column Filter node.

Now that you have cleaned up the data in the second sheet you can combine all the data together in one table before proceeding with the next step.
To do so search, drag, and drop the Concatenate node from the node repository into the workflow editor. Connect the first input data table port to the output port of the first Excel Reader node and the second input data table port to the output port of the Column Filter, which contains the cleaned-up data from the second Excel Reader node.

Open the Concatenate node configuration dialog to select how to combine the input columns and choose what to do in case there are duplicate row identifiers (RowIDs). 
Select Union to use all columns from all input tables and Append suffix so that the output table will contain all rows from both input tables, but duplicate RowIDs are labeled with a suffix.

To visualize the data, you will need to use the view nodes. For example, to build a bar chart search for the Bar Chart node in the node repository, drag and drop it into the workflow editor and connect it to the Concatenate node. Click the configuration cog button in the node action bar to open the configuration dialog of the node. Here you can configure the node to visualize your data and also have a look at the resulting plot preview right away.

Select the column that contains the item names as the category dimension, select the sum as the aggregation method and finally include the column Amount as the quantitative dimension of the bars.

Click Save & execute to see the preview of the bar chart. When you are satisfied with the generated plot, click Ok.

To see the resulting output visualization, you can click the magnifier view button in the node action bar.

Now you want to perform a more advanced set of operations on your data by using a third sheet that is available in the xls file: the Dictionary sheet. To do so you will first need a third Excel Reader node and you will configure so that it reads the data from the sheet called Dictionary. The data table is made of three columns: the Dict-Item column that contains the key values of the dictionary, the column Dict-Volume that contains the corresponding dictionary values. The Dict-Volume column, however, contains missing values which are instead present in a third column, empty_C. You can use the Column Merger node to combine the two columns into one and filter out the second column. In the Column Merger configuration dialog, select the Primary column to be the Dict-Volume column and the Secondary column to be the empty_C column. Then select the first option in order to replace the values in the primary column and delete the secondary column.

Now, first change the column type of the Dict-Volume column from string to number. You can do it by using a String To Number node. Then you want to create a table that contains the following columns: a column Item with a list of all the available items, a column Amount with the corresponding amount of those items and a column Dict-Volume containing the volumes of the listed items. The first two columns are available at the output port of the Concatenate node, resulting from the combination of the first two sheets of the xls file, while the third column is contained in the dictionary table. In order to combine these information in one table, matching the items names, you need to use a Value Lookup node.

The Value Lookup node has two inputs: a data table and a dictionary table. Connect the first input port to the output port of the Concatenate node which contains the data table and the second input port to the output port of the String To Number node which contains the dictionary table. Now open the configuration dialog of the Value Lookup node. From the data table, select the column Item that is used to look up values in the dictionary table. 

From the dictionary table, instead, select the column Dict-Item that contains the search keys. In the Output section select the Dict-Volume column from the second table to be included in the output table. Click Ok and execute the node. 

Finally, you may want to calculate the total volume for each item and the grand total volume of all the items listed. To do this, you can use the Row Aggregator node, which aggregates columns using an aggregation function. The node has two output ports: the first one outputs the results of the aggregation function, while the second one, if the corresponding setting is enabled in the node configuration dialog, contains the grand total value. 

Once you have added the Row Aggregator node into the workflow editor and connected it to the output port of the Value Lookup node, open the node configuration dialog.

Here, select Item as the Category column and Sum as the aggregation function. The column that we want to aggregate on for each item in the Category column is the Dict-Volume column, which is then added to the list of included columns.

Finally, since you want to calculate the grand total of the volume of all the items available in stock, you can select the column Amount to be the Weight column and activate the option to show additional “grand totals” at the second output port.

Click Ok and execute the node.

Now, you can view the output table in the node monitor, at the bottom of the workbench, when you select the executed Row Aggregator node.

You can switch between viewing the output of the first output port data table, with the results of the aggregation, and the output of the second output port data table with the results of the grand total calculation.  

The input(s) is the data that the node processes via the node ports, and the output(s) are the resulting data. Each node has specific settings, which you can adjust in a configuration dialog. Different types are represented by different node ports. Only ports of the same type indicated by the same color can be connected. Here are some examples of ports for frequently used data types.

A node can be in four different states. The node status is shown by a traffic light below each node.

A series of interconnected nodes defines a workflow. Nodes can be connected via their input and output ports to form a workflow. Once a workflow is executed, the data inside the workflow flows then from left to right through the connections, either step-by-step or entirely.

Components are really KNIME nodes that you create with a KNIME workflow. They encapsulate and abstract functionality, can have their own dialog, and can have their own sophisticated, interactive views. Components can be reused in your own workflows but also shared with others: via KNIME Community Hub.

Metanodes allow you to organize your workflows better: you can take part of a larger workflow and collapse it into a gray box that hides that part of the workflow’s functionality. It also makes it easier for others to understand what your workflow does as you can structure it a bit more hierarchically.