I’m wondering whether you would like to add an automatic money calculation function to the workflow App for goods purchasing requests. The App will allow you to calculate not only the total and subtotal, but also to change the formula depending on the conditions.

In this post, I would like to illustrate how to implement a system that not only calculates the total amount based on the purchase list but also does a discount calculation which deducts 50% from payments exceeding $1000 of the total amount using a split in the workflow diagram. A Table-type Data Item and a Update Data are vital elements for the design of this App.

Calculation of the Total Amount with a Table-type Data Item

First of all, we’d like you to create an App, setting a Table-type Data Item for listing the purchased items and make it calculate the total automatically.

Workflow Diagram

Please create a new App and set up the workflow diagram as follows:

Data Items

Let’s prepare the following data items.

Data Item NameData-typeField NameRemarks
Purchase listTableq_purchase_listSet the 4 sections, Description (String)/ Unit Price (Numeric)/ Quantity (Numeric)/ Subtotal (Numeric)
TotalNumeric-typeq_totalAutomatically input the total value of: Purchase list–Subtotal

Purchase List Settings

In Purchase List (Table-type Data Item) set up 4 table columns, which are labelled Description, Unit Price, Quantity, and Subtotal respectively.

In the Subtotal column the subtotal of each row in the table is calculated and saved. Check the “Show total value at the bottom of list” box as well. In addition, it is mandatory to set the Field Name for a column that is set to display the sum. Please be sure to set it. (This Field Name does not have to start with “q_”.)

Then you should set up a Numeric-type Data Item that saves the total value of the Table-type Data Item using the arithmetic expression settings window. The expression is automatically inserted into the text box.

Data editing permission Settings

Please set up as in the following figure.

TitleEditable Only display
Purchase listEditable Only display
TotalNo display Only display

You’ve created an app that calculates the total amount from the Purchase list using a Table-type Data Item. Please exit editing and release it now to see how it works.

When you finish the Task after entering the unit price and quantity of an item in the Purchase list, the total amount will be saved in the Total section.

Discount Calculations Using Update Data

Now let’s implement a workflow that performs automatic calculations under the condition of a 50% discount for payments where the total is over $1000.

Workflow Diagram

Let’s add some changes to the initial workflow diagram that you made as follows:

Set an Update Data icon in each split flow where the condition of the Task is set to more than $1000 and less than $1000 in the total amount. That enables the token to advance to the Task and set the condition of a 50% discount for payments exceeding $1000 in the total amount.

Settings in Exclusive Gateway (XOR)

You use an Exclusive Gateway (XOR) to control the flow based on whether the total amount is over $1000.

You have to add a flow for cases of over $1000 and set its destination to “Discount”, whereas you set the destination of the Default Flow to “No Discount”.

For the condition of the Total which is set over $1000, the Conditional Expression Setting is set as follows.

This setting enables the token to advance to the Discount Processing Task if the Total is $1000 or more, whereas the token advances to the No Discount Task if the total is less than $1000.

Data Item Settings

Please add a Numeric-type Data Item called “Total Discounted Amount” to save the discounted total.

Data Item NameData-typeField NameRemarks
Total Discounted AmountNumeric-typeq_discounted_total
Total Discounted AmountNo display Only display

Settings in Update Data

Let’s set up two Update Data Steps respectively for the No Discount and Discount branches.

No Discount

Set up an expression for the Total which is less than $1000. Since it will not apply any discount, the value of Total should be saved in the Total Discounted Amount data item.


Set up an expression for the Total which is over $1000. A 50% discount is given to the amount over $1000 so the expression is set as follows:

100000 + (#q_total - 100000) * 0.5

* For the Numeric-type, numbers below the range of decimal digits specified in the settings of the Data item are truncated (e.g. if the range of decimal digits is 0, then the result of 1.5 (3 * 0.5) becomes 1 due to rounding down the first decimal place). The same thing will perform in the Numeric-type item in the table columns.

The settings of the App are now complete. You have to exit editing and release it to see how it works. In particular, I would like you to check that splitting by the Total is working and check for any mistakes in discount calculations.

Use of an Arithmetic expression in the Settings window (Numeric-type Data Item)

This time I used Update Data for the discount calculations to cope with the splitting process. However, the Expression field in the settings window of a Numeric-type Data Item can be used for arithmetic operations as well. For example, you can achieve a 50% discount by setting the same expression as with the Discount Task like in the figure below. However, you should remember that the Expression field in the settings window can’t set a split condition for a 50% discount for payments over $1000.

Although within the settings window of a Numeric-type Data Item it is not possible to change expressions according to any conditions, it may not be necessary if the App doesn’t require a splitting process. Please use the property according to the implementation you want.

As explained above, the use of a Table-type Data Item and Update Data will make it possible to perform various calculations. Questetra BPM Suite will help with troublesome monetary calculations that can change the formula according to the conditions faster without bothering any staff members.

3 thoughts on “Let’s Calculate the Total Amount Automatically”

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