Build a Simple HRM App 5: Smarten Up Your App with Business Logic - Mendix 6 How-to's

1 Introduction

This how-to is based on the video “Build a simple HRM app: Smarten up your app with business logic,” which is part of the Getting Started videos.

This is the last how-to in a series of five on how to create a simple HRM application. In this how-to, you learn how to smarten up your application by adding business logic.

After using this how-to, you will know how to do the following:

How to create a microflow
How to build business logic

2 Prerequisites

Before you can start with this how-to, make sure you have completed the following prerequisite:

Use the fourth how-to in this series: Build a Simple HRM App 4: Enrich the GUI with Filter Options

3 Creating a Microflow

In this section you will create a microflow.

3.1 Adding an Action Button That Calls a Microflow

To add an action button that calls a microflow, follow these steps:

Open the Employee_Overview page of the MyFirstModule module.
Right-click the grid control bar of the data grid in the Master Detail container and select Add button > Action. To learn more about action buttons, see the Action Button section of the Mendix Reference Guide.
Double-click the new button and change the caption of the button to Promote.
Select Call a microflow as the on click event: To learn more about a microflow, see the Microflows chapter of the Mendix Reference Guide.
Click Select to select a microflow:
Click the MyFirstModule module, and then click New to add a new microflow to the Responsive module:
Enter Employee_Promote in the Name field, then click OK to create the microflow:
Right-click the new button and select Go to microflow:

The microflow should look like this:

3.2 Adding an Exclusive Split

To add an exclusive split, follow these steps:

Select an exclusive split from the toolbar of the microflow editor: To learn more about exclusive splits, see the Exclusive Split chapter of the Mendix Reference Guide.
Click a point on the line to add the exclusive split to the flow:
Double-click the new exclusive split to open the properties editor:
Enter Level? in the Caption field.
Place your cursor in the Expression field and then press CTRL + SPACE to bring up a list of suggestions: To learn more about microflow expressions, see the Microflow Expressions chapter of the Mendix Reference Guide.
Select $Employee (MyFirstModule.Employee) from the list of suggestions. This employee object corresponds to the input object of the microflow:
Add a forward slash (“/”) to the value in the Expression field. This will show all the attributes of the employee object:
Select Level (Enumeration ‘Level’):
Click OK. The exclusive split will now evaluate the values from the Level attribute:
Double-click a point on the line between the exclusive split and the end event, and then select Junior from the Value drop-down menu:
Click OK. When the employee in the input parameter has the Junior level, this path will be executed:
Select an end event from the toolbar of the microflow editor: To learn more about an end event, see the End Event section of the Mendix Reference Guide.
Add an end event to the flow:
Drag a line from the exclusive split to the new end event.
Double-click a point on the line between the exclusive split and the new end event, and then select Medior in the Value drop-down menu:
Click OK.
Repeat steps 10–16 for the Senior and (empty) values. The microflow should look like this:

3.3 Adding Activities to the Microflow

To add activities to the microflow, follow these steps:

Drag a Change object activity from the Toolbox to the Junior path: To learn more about activities, see the Activities chapter of the Mendix Reference Guide.
Double-click the new change object activity to open the Change Object properties editor:
Select Employee (MyFirstModule.Employee) from the input Variable drop-down menu:
Set Commit to Yes. This will save the change to the database.
Set Refresh in client to Yes. This will update the value in the UI.
Click New to add a new change item:
Select Level (Enumeration ‘Level’) from the Member drop-down menu:
Click Generate:
Select Medior from the Constant drop-down menu, then click OK:
Click OK to save the change object properties. The microflow will look like this:
Repeat steps 1–10 for the Medior path. Make sure that you set the level value to Senior. The microflow should then look like this:
Drag a Show message activity from the Toolbox to the Senior path:
Double-click the show message activity to open the Show Message properties editor.
Enter Employee is already at senior level in the Template field, then click OK:
Drag a Change object activity from the Toolbox to the path that will be executed when the employee has no level.
Repeat steps 2 through 10 for this new change object activity and make sure that you set the level value to Junior. The microflow will look like this:

4 Viewing Your App

To view your app, follow these steps:

Click Run in Sandbox, then Save and continue, and then View App.
Click Employees in the navigation list, and then select an employee with the Medior level.
Click PROMOTE. The level of the employee will change from Medior to Senior.
Click PROMOTE. You will see a message that you cannot promote the employee because the employee is already Senior.