Your First Application in 20 Minutes › Defining the Project Entity › Using Continuation Triples to Make Fields Optional › More About Optionality

More About Optionality

When your end users enter data, they typically enter data in every field. You can specify that some fields are mandatory, while others are optional. If you do not specify optionality, the default is that they are mandatory.

Primary key fields must always be mandatory, so you should leave the Project ID field as it is. But, your end users can use a Project ID that is descriptive enough that they do not need to enter any data in the Project Description field. When end users create projects, they may not have a start or end date yet.

If end users leave a mandatory field blank and then try to close the dialogs, a message dialog prompts them to enter data for the blank mandatory field, and does not let them close the dialog until they do. Since this processing is defined as part of the pattern library and not hard-coded into CA Plex, you can adapt it as required (but this concept is not explained in this tutorial).

To make fields optional:

1. Click the Entities toolbar button to set the Object Browser to display entities.

   

2. Select the Project entity in the Object Browser and click the Inspect toolbar button.

   

   This focuses the Model Editor on the Project entity, showing only the triples that define that entity.

3. Click in the center of the triple Project has Project Description to select it.
4. Drag it to the source object (top left) box in the Model Editor:

   

5. Select optionality SYS from the verb (top middle) list, and Optional from the target object (top right) list.
6. Press Enter.

   You have entered the continuation triple:

   Project has Project Description
   ...optionality triples Optional

   Note: If you do not see this view, click the One Level toolbar button to set the Model Editor to show a single level of information.

7. In the same manner, make the Project Start Date and Project End Date fields optional.
8. Refresh the Model Editor: