Organize Data Models under Use Cases

In helping you organize your modeling project, use cases can act as generic containers for all software development artifacts. Development teams can group and locate design artifacts by navigating use cases.

In this tutorial we are going to show you how to create a new data model (i.e. entity relationship diagram) and associate that with a use case. And in future, you can easily identify existing associations as such by use cases and conveniently, be taken to the related diagrams right on the spot in just a few clicks.

Software we’ll use
In the demo, we’ll be using Agilian Standard Edition. If you like, you are welcome to download a free evaluation copy and the sample project files below to follow the example with.

• PatientInformation_before.vpp
• PatientInformation_after.vpp

Steps to create a data model and associate it with a use case

We’ll begin with the sample use case diagram below.

01 – sample use case diagram

1. Select the use case Record patient visit report. Click on the icon Sub-diagrams.
   

   02 – the sub-diagram icon on use case

2. From the popup menu, select Add > Other Diagrams > Database Modeling > Entity Relationship Diagram.
   

   03 – select to create an entity relationship diagram

3. A new entity relationship diagram (ERD) will open. (Initially, it is named Record patient visit report after the use case but you are free to change it as you wish.) At the top right corner, select Conceptual Model.
   

   04 – a new entity relationship diagram with the same name as the use case

4. From the diagram toolbar, drag Entity onto the diagram.
   

   05 – drag an entity onto diagram

5. Name the new entity Patient. Right click on it and then select New column to create 2 columns – name and address.
   

   06 – add new columns to an entity

6. Create a relationship from the entity Patient. Select Patient and drag the icon One-to-Many Relationship -> Entity to the right. Release your mouse button at where you want to place the new entity.
   

   07 – create a new one-to-many relationship

7. Name the new entity Visit. Add 3 columns to it – visitDate, visitTime and description.
   

   08 – the entity visit

How to view the list of existing diagram associations and jump to one

Let’s say some time in the future you’re studying the sample use case diagram again. And you want to check and see which diagrams are related to the use case.

To do that, simply select the use case Record patient visit report and click the icon Sub Diagrams. On the popup menu, you will see its related diagrams listed at the top (i.e. Record patient visit report). If you click it, the entity relationship diagram we drew earlier will open. So you won’t have to search around to locate it.

09 – see list of existing associated diagrams

Related Links

• Watch the video version of this tutorial
• YouTube video – how to define a custom property for use case
• YouTube video – Drill down from Business Process Diagram to Data Model

Related Articles

• know-how – how to list out all use cases in the current project